200 resultados para Tree Breeding Strategies
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Genetic diversity of contemporary domesticated species is shaped by both natural and human-driven processes. However, until now, little is known about how domestication has imprinted the variation of fruit tree species. In this study, we reconstruct the recent evolutionary history of the domesticated almond tree, Prunus dulcis, around the Mediterranean basin, using a combination of nuclear and chloroplast microsatellites [i.e. simple sequence repeat (SSRs)] to investigate patterns of genetic diversity. Whereas conservative chloroplast SSRs show a widespread haplotype and rare locally distributed variants, nuclear SSRs show a pattern of isolation by distance with clines of diversity from the East to the West of the Mediterranean basin, while Bayesian genetic clustering reveals a substantial longitudinal genetic structure. Both kinds of markers thus support a single domestication event, in the eastern side of the Mediterranean basin. In addition, model-based estimation of the timing of genetic divergence among those clusters is estimated sometime during the Holocene, a result that is compatible with human-mediated dispersal of almond tree out of its centre of origin. Still, the detection of region-specific alleles suggests that gene flow from relictual wild preglacial populations (in North Africa) or from wild counterparts (in the Near East) could account for a fraction of the diversity observed.
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Agro-ecosystems have recently experienced dramatic losses of biodiversity due to more intensive production methods. In order to increase species diversity, agri-environment schemes provide subsidies to farmers who devote a fraction of their land to ecological compensation areas (ECA). Several studies have shown that invertebrate biodiversity is actually higher in ECA than in nearby intensively cultivated farmland. It remains poorly understood, however, to what extent ECA also favour vertebrates, such as small mammals and their predators, which would contribute to restore functioning food chains within revitalized agricultural matrices. We studied small mammal populations among eight habitat types - including wildflower areas, a specific ECA in Switzerland - and habitat selection (radiotracking) by the barn owl Tyto alba, one of their principal predators. Our prediction was that habitats with higher abundances of small mammals would be more visited by foraging Barn owls during the period of chicks' provisioning. Small mammal abundance tended to be higher in wildflower areas than in any other habitat type. Barn owls, however, preferred to forage in cereal fields and grassland. They avoided all types of crops other than cereals, as well as wildflower areas, which suggests that they do not select their hunting habitat primarily with respect to prey density. Instead of prey abundance, prey accessibility may play a more crucial role: wildflower areas have a dense vegetation cover, which may impede access to prey for foraging owls. The exploitation of wildflower areas by the owls might be enhanced by creating open foraging corridors within or around wildflower areas. Wildflower areas managed in that way might contribute to restore functioning food chains within agro-ecosystems.
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We characterize divergence times, intraspecific diversity and distributions for recently recognized lineages within the Hyla arborea species group, based on mitochondrial and nuclear sequences from 160 localities spanning its whole distribution. Lineages of H. arborea, H. orientalis, H. molleri have at least Pliocene age, supporting species level divergence. The genetically uniform Iberian H. molleri, although largely isolated by the Pyrenees, is parapatric to H. arborea, with evidence for successful hybridization in a small Aquitanian corridor (southwestern France), where the distribution also overlaps with H. meridionalis. The genetically uniform H. arborea, spread from Crete to Brittany, exhibits molecular signatures of a postglacial range expansion. It meets different mtDNA clades of H. orientalis in NE-Greece, along the Carpathians, and in Poland along the Vistula River (there including hybridization). The East-European H. orientalis is strongly structured genetically. Five geographic mitochondrial clades are recognized, with a molecular signature of postglacial range expansions for the clade that reached the most northern latitudes. Hybridization with H. savignyi is suggested in southwestern Turkey. Thus, cryptic diversity in these Pliocene Hyla lineages covers three extremes: a genetically poor, quasi-Iberian endemic (H. molleri), a more uniform species distributed from the Balkans to Western Europe (H. arborea), and a well-structured Asia Minor-Eastern European species (H. orientalis).
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RESUME Le cancer du col de l'utérus, deuxième cause de mort par cancer chez la femme, a pu être associé à une infection par plusieurs types de virus du Papillome Humain (HPV), et en particulier HPV 16. Les vaccins prophylactiques sont efficaces à prévenir le cancer du col utérin alors que les lésions de haut grade sont généralement traitées par ablation chirurgicale et par d'éventuels traitements additionnels. Les risques de récurrence liés aux ablations et le taux de mortalité (50%) lié au cancer, démontrent le besoin de développer des stratégies alternatives afin de cibler les lésions précancéreuses. A ce jour, les vaccins thérapeutiques ont démontré peu de résultats cliniques, contrastant avec les régressions de tumeurs ectopiques observées après vaccination dans des modèles murins avec tumeurs associées à HPV. L'induction de réponses immunitaires protectrices dans la muqueuse génitale semble être cruciale pour l'efficacité des vaccins thérapeutiques HPV et évaluer leur efficacité dans un modèle murin avec tumeurs-HPV génitales représente un pré-requis important avant de procéder à des études cliniques. Par conséquent, nous avons établi un modèle murin orthotopique où des tumeurs se développent dans (a muqueuse génitale après une instillation intra-vaginale (i.vag) de cellules tumorales exprimant les oncogènes E6/E7 d'HPV 16 et transduites par un vecteur lentiviral codant la luciferase afin de suivre le développement de ces tumeurs in vivo par imagerie. La caractérisation histologique a démontré que les tumeurs grandissaient dans l'épithélium vaginal et en accord avec leur localisation, des cellules Τ CD8 spécifiques à E7 induites par la tumeur n'étaient détectées que dans la muqueuse génitale et les ganglions drainants. Une infiltration de cellules Τ régulatrices a aussi été mise en évidence, empêchant la régression spontanée de ces tumeurs. Par conséquent, ce modèle devrait être plus adéquat pour tester des stratégies thérapeutiques, étant donné qu'il partage certaines similarités immunologiques avec les lésions génitales naturelles causées par HPV. Etant donné que les oncogènes E6 et E7 d'HPV sont nécessaires à la maintenance du phénotype cancéreux des cellules cervicales, elles représentent des antigènes cibles pour la vaccination thérapeutique. Nous avons démontré que des souris immunisées par voie sous-cutanée (s.c.) avec une dose d'un vaccin à base de polypeptide E7 d'HPV 16 et d'adjuvants, présentaient de nombreuses cellules Τ CD8 sécrétant de l'IFN-γ spécifiquement à E7 dans leurs organes lymphatiques mais également dans la muqueuse génitale. De plus, le manque de corrélation entre les réponses spécifiques mesurées dans la périphérie et dans la muqueuse génitale souligne la nécessité et l'importance de déterminer les réponses immunitaires localement là où les lésions dues à HPV se développent. Si une vaccination par voie muqueuse est plus propice à traiter/régresser des infections génitales/tumeurs que le voie parentérale est un sujet débattu. Nos données montrent que seule la voie s.c. était capable de régresser la quasi totalité des tumeurs génitales chez la souris bien que des réponses CD8 spécifiques à E7 similaires étaient mesurées dans la muqueuse génitale après des vaccinations intra-nasale et i.vag. Afin d'augmenter la réponse spécifique au vaccin dans la muqueuse génitale, des immunostimulants ont été administrés par voie i.vag après vaccination. Nous avons démontré qu'une application i.vag d'agonistes des Toll like receptors après une vaccination s.c. induisait de manière significative une augmentation des cellules Τ CD8 sécrétant de l'IFN-γ spécifiquement à E7 dans la muqueuse génitale. Plus précisément et concernant les CpG et Poly l:C, l'effet était probablement associé à une attraction locale des cellules Τ CD8 et deuxièmement dépendait respectivement des voies de signalisation TLR9 et TLR3/Mda5. Finalement, cette stratégie combinatoire a permis de régresser des grosses tumeurs génitales chez la souris, suggérant qu'une telle immunothérapie pourrait adéquatement traiter des lésions dues à HPV chez les femmes. SUMMARY Cervical cancer is the second leading cause of cancer mortality in women worldwide and results from an infection with a subset of Human Papillomavirus (HPV), HPV 16 representing the most prevalent type. The available prophylactic vaccines are an effective strategy to prevent cervical cancer while already established high grade lesions usually require surgical ablation of lesion with possible additional treatments. Recurrence risks linked to conventional ablations and the high mortality (50%) related to cervical cancer demonstrate the need for alternative strategies like immunotherapies to target pre¬cancerous lesions. Until now, therapeutic vaccines only showed limited clinical results, which strongly contrast with the regression of ectopic tumors observed in the available murine HPV tumor models after vaccination. Induction of protective immune responses in the genital mucosa (GM) may be crucial for efficacy of HPV therapeutic vaccines and evaluating their efficacy in a murine model with genital HPV- tumors represents an important prerequisite for clinical trials. Thus, we have here established an orthotopic mouse model where tumors in the GM develop after an intravaginal (i.vag) instillation of HPV 16 E6/E7 oncogenes-expressing tumor cells transduced with a luciferase encoding lentivirus vector for in vivo imaging of tumor growth. Histological characterization showed that tumor grew within the vaginal epithelium and according to their mucosal location tumor- induced E7-specific CD8 Τ cells were restricted to the GM and genital draining lymph nodes together with high Τ regulatory cells infiltrates preventing spontaneous regression. Consequently, sharing several immunological similarities with natural genital HPV lesions, this novel genital tumor model may be more adequate to test therapeutic strategies. As E6 and/or E7 HPV oncogenes expression is required for the maintenance of the cancerous phenotype of cervical cells, they represent target antigens for therapeutic vaccination. We reported that mice subcutaneously (s.c.) immunized once with an adjuvanted HPV 16 E7 polypeptide vaccine harbored high E7-specific IFN-γ secreting CD8 Τ cells in their lymphoid organs and more importantly in the GM. In addition, the lack of correlation between specific responses measured in the periphery with those measured in the GM highlighted the necessity and relevance to determine the immune responses locally where HPV 16-induced lesions develop. Whether a mucosal route of immunization is better to treat/regress genital infections/tumors than parenteral immunization is still debated. Our data shows that although similar E7-specific IFN-γ secreting CD8 Τ cells responses were measured in the GM upon mucosal routes of E7 vaccine delivery (nasal and vaginal immunizations), only the s.c immunization was able to regress at least all genital tumors in mice. To further increase the vaccine-specific responses in the GM, immunostimulatory agents were i.vag administrated after vaccination. We demonstrated that a single i.vag application of toll like receptor (TLR) agonists after a s.c. E7 vaccination induced a significant increase of E7-specific IFN-γ secreting CD8 Τ cells in the GM. More precisely, regarding CpG and Poly l:C, the effect is most probably associated with a local attraction of total CD8 Τ cells and secondly depends on TLR9 and TLR3/Mda5 signaling pathways, respectively. Finally, this combinatorial strategy induced tumor regression in mice harboring large genital tumors, suggesting that such an immunotherapy could be adequate to treat HPV-induced lesions in women.
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Abstract This thesis proposes a set of adaptive broadcast solutions and an adaptive data replication solution to support the deployment of P2P applications. P2P applications are an emerging type of distributed applications that are running on top of P2P networks. Typical P2P applications are video streaming, file sharing, etc. While interesting because they are fully distributed, P2P applications suffer from several deployment problems, due to the nature of the environment on which they perform. Indeed, defining an application on top of a P2P network often means defining an application where peers contribute resources in exchange for their ability to use the P2P application. For example, in P2P file sharing application, while the user is downloading some file, the P2P application is in parallel serving that file to other users. Such peers could have limited hardware resources, e.g., CPU, bandwidth and memory or the end-user could decide to limit the resources it dedicates to the P2P application a priori. In addition, a P2P network is typically emerged into an unreliable environment, where communication links and processes are subject to message losses and crashes, respectively. To support P2P applications, this thesis proposes a set of services that address some underlying constraints related to the nature of P2P networks. The proposed services include a set of adaptive broadcast solutions and an adaptive data replication solution that can be used as the basis of several P2P applications. Our data replication solution permits to increase availability and to reduce the communication overhead. The broadcast solutions aim, at providing a communication substrate encapsulating one of the key communication paradigms used by P2P applications: broadcast. Our broadcast solutions typically aim at offering reliability and scalability to some upper layer, be it an end-to-end P2P application or another system-level layer, such as a data replication layer. Our contributions are organized in a protocol stack made of three layers. In each layer, we propose a set of adaptive protocols that address specific constraints imposed by the environment. Each protocol is evaluated through a set of simulations. The adaptiveness aspect of our solutions relies on the fact that they take into account the constraints of the underlying system in a proactive manner. To model these constraints, we define an environment approximation algorithm allowing us to obtain an approximated view about the system or part of it. This approximated view includes the topology and the components reliability expressed in probabilistic terms. To adapt to the underlying system constraints, the proposed broadcast solutions route messages through tree overlays permitting to maximize the broadcast reliability. Here, the broadcast reliability is expressed as a function of the selected paths reliability and of the use of available resources. These resources are modeled in terms of quotas of messages translating the receiving and sending capacities at each node. To allow a deployment in a large-scale system, we take into account the available memory at processes by limiting the view they have to maintain about the system. Using this partial view, we propose three scalable broadcast algorithms, which are based on a propagation overlay that tends to the global tree overlay and adapts to some constraints of the underlying system. At a higher level, this thesis also proposes a data replication solution that is adaptive both in terms of replica placement and in terms of request routing. At the routing level, this solution takes the unreliability of the environment into account, in order to maximize reliable delivery of requests. At the replica placement level, the dynamically changing origin and frequency of read/write requests are analyzed, in order to define a set of replica that minimizes communication cost.
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Background: Several studies have shown that treatment with HMG-CoA reductase inhibitors (statins) can reduce coronary heart disease (CHD) rates. However, the cost effectiveness of statin treatment in the primary prevention of CHD has not been fully established. Objective: To estimate the costs of CHD prevention using statins in Switzerland according to different guidelines, over a 10-year period. Methods: The overall 10-year costs, costs of one CHD death averted, and of 1 year without CHD were computed for the European Society of Cardiology (ESC), the International Atherosclerosis Society (IAS), and the US Adult Treatment Panel III (ATP-III) guidelines. Sensitivity analysis was performed by varying number of CHD events prevented and costs of treatment. Results: Using an inflation rate of medical costs of 3%, a single yearly consultation, a single total cholesterol measurement per year, and a generic statin, the overall 10-year costs of the ESC, IAS, and ATP-III strategies were 2.2, 3.4, and 4.1 billion Swiss francs (SwF [SwF1 = $US0.97]). In this scenario, the average cost for 1 year of life gained was SwF352, SwF421, and SwF485 thousand, respectively, and it was always higher in women than in men. In men, the average cost for 1 year of life without CHD was SwF30.7, SwF42.5, and SwF51.9 thousand for the ESC, IAS, and ATP-III strategies, respectively, and decreased with age. Statin drug costs represented between 45% and 68% of the overall preventive cost. Changing the cost of statins, inflation rates, or number of fatal and non-fatal cases of CHD averted showed ESC guidelines to be the most cost effective. Conclusion: The cost of CHD prevention using statins depends on the guidelines used. The ESC guidelines appear to yield the lowest costs per year of life gained free of CHD.
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Le rétinoblastome représente 11% de tous les cancers apparaissant pendant la première année de vie. Pour éviter les effets secondaires de la chimiothérapie systémique ou de la radiothérapie externe, de nouveaux médicaments et de nouvelles techniques de traitement focalisé ont été développés. Des voies d'administration telles la voie périoculaire (topotécan) ou la voie artérielle ophtalmique directe (carboplatine) sont utilisées aujourd'hui dans certains cas résistants. La radiothérapie actuelle, appliquée exclusivement en deuxième intention, fait appel également à des techniques ciblées, permettant d'éviter les tissus sains et de réduire le risque de cancers radio-induits non oculaires. La radiothérapie stéréotaxique conformationnelle ou conformale et la proton-thérapie font ainsi partie du nouvel arsenal thérapeutique du rétinoblastome. Retinoblastoma represents 11% of all cancers during the first year of life. New drugs and focal treatments have been developed in order to avoid the side effects of systemic chemotherapy and external radiotherapy. New targeted and local administration strategies such as periocular chemotherapy (topotecan) or direct ophthalmic artery delivery (carboplatin), are already used today in selected resistant cases. Radiotherapy, presently indicated only as a second-line treatment, is also subject to new techniques, targeting tumors more closely to avoid involving healthy tissue and reduce the risk of radio-induced nonocular tumors. Stereotactic conformal radiotherapy and proton therapy may thus be included in the new range of treatment methods in retinoblastoma
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Résumé : Les anticorps monoclonaux ont une place de plus en plus prépondérante dans le traitement des lymphomes et leucémies. Dans cette étude, trois anticorps monoclonaux murins, dirigés contre les antigènes CDS, CD71 et HLA-DR exprimés à la surface des cellules de leucémies lymphoïdes chroniques (LLC), ont été évalués. In vitro, les anticorps radiomarqués ont montrés des bonnes liaisons spécifiques sur les différentes cellules cibles. L'anti-CD71 inhibait la prolifération de la plupart des lignées cellulaires testées avec une accumulation des cellules en phase S précoce du cycle cellulaire. L'anti-HLA-DR inhibait aussi la prolifération des lignées leucémique JOK1-5.3 et lymphoïde Daudi. Cette inhibition était associée à une agrégation des cellules. Aucune induction d'apoptose n'a pu être clairement observée avec ces anticorps. L'anti-CD5 n'a montré aucun effet d'inhibition de croissance in vitro. In vivo, l'injection des anticorps individuellement augmentait significativement la survie médiane de souris SCID greffées avec des cellules JOK1-5.3 en i.p. De plus, l'anticorps antiCD5 combiné à l'anti-HLA-DR ou l'anti-CD71, sous certaines conditions, inhibait complètement le développement tumoral dans la quasi totalité des souris traitées avec une augmentation significative de l'efficacité comparée aux anticorps seuls. L'augmentation de l'efficacité thérapeutique des anticorps monoclonaux par les cytokines, dont l'IL-2, a déjà été montrée dans la littérature. Au regard du meilleur comportement de l'IL-2 sous la forme complexée à un anticorps anti-IL-2, nous avons évalué l'efficacité de l'IL-2/anti-IL-2 seul ou combinés au rituximab chez différents modèles tumoraux s.c. (BL60.2, Daudi, Ramos) ou i.p. (JOK15.3) de souris SCID. Le complexe IL-2/anti-IL-2 a montré un effet anti-tumoral dans les souris greffées avec BL60.2 et Daudi. Le traitement IL-2/anti-IL-2 combiné au rituximab a montré une efficacité accrue chez des souris avec BL60.2 par rapport au rituximab seul. En revanche, nous n'avons pas observé de différence avec IL-2/anti-IL-2 seul.Aussi, nous avons évalué l'utilisation de l'agent couplant tri-fonctionnel TMEA pour produire des anticorps bispecifiques. Les expériences préliminaires avec les anticorps rituximab et herceptine, ont mis en évidence sur gel SDS-Page la formation de dimers (~100kDa) et de trimers (~150kDa). Les anticorps bispecifiques sont composés d'un fragment Fab' d'une spécificité et de un ou deux fragments Fab' de l'autre spécificité permettant de moduler la capacité de liaison. Nous avons enfin montré qu'une construction anti-CD5/anti-CD20 était capable de se lier indépendamment ou simultanément à ses antigènes cibles. En conclusion, ce travail a montré l'efficacité thérapeutique des trois anticorps monoclonaux étudiés dans un model de LLC in vivo, et plus particulièrement l'intérêt de certaines combinaisons. D'autre part, nous avons montré l'efficacité anti-tumorale du complexe IL-2/anti-IL-2 in vivo. Des études futures devront permettre de définir un régime favorable pour augmenter l'efficacité de la thérapie avec les anticorps monoclonaux. Enfin, nous avons montré la faisabilité d'utiliser l'agent couplant TMEA pour produire des anticorps bispécifiques fonctionnels.Abstract : Monoclonal antibody (mAb) therapy has become an integral part in different treatments of lymphomas and leukaemias. In this study, we describe three murine mAbs directed against the CD5, CD71 and HLA-DR antigens expressed on chronic lymphocytic leukaemia cells (CLL). In vitro, radiolabeled purified mAbs showed good specific binding on live target cells. Anti-CD71 mAb inhibited proliferation of most cell lines with an accumulation of responding cells in early S-phase of the cell cycle, but without induction of apoptosis. Anti-HLA-DR mAb showed proliferation inhibition of leukaemia JOK1-5.3 and lymphoid Daudi cells, associated with cell aggregation, but again no specific sign of apoptosis was observed. Anti-CD5 mAb did not show any growth inhibitory effect in vitro. In vivo, in a model of SCID mice grafted i.p. with JOK1-5.3 cells, injection of individual mAbs induced significant prolongation of median survival, up to complete inhibition of tumour growth in some mice. Antibody combination of anti-CD5 with anti-HLA-DR or anti-CD71, evaluated in an early treatment, completely inhibited tumour growth in most mice, with a significant efficacy enhancement as compared to mAb used as single agents. Previous reports described the improved efficacy of mAb therapy when combined with cytokines such as IL-2. Relying further on the improved efficacy of IL-2 when administered as an immune complex with anti-IL-2 mAb, we evaluated the anti-tumour effect of the IL-2/anti-IL-2 complex alone or combined with rituximab in subcutaneous (BL60.2, Daudi, Ramos) or i.p. (JOK1-5.3) tumour models in SCID mice. The IL-2/anti-IL-2 complex demonstrated an anti-tumour effect in BL60.2 and Daudi grafted SCID mice. Combination of IL-2/anti-IL-2 treatment with rituximab showed increased efficacy as compared to rituximab alone in BL60.2 grafted mice. However, no difference was observed with IL-2/anti-IL-2 complex alone in these experiments. Finally, we evaluated the feasibility of producing bispecific antibodies (bsAbs) using a trifunctional coupling agent, called TMEA. In preliminary experiments coupling rituximab with herceptine Fab' fragments we obtained the formation of dimers (~100kDa) and trimers (~150kDa) as observed on SDS-Page gel. This method allowed us to produce bsAb with one Fab' fragments of one specificity and one or two Fab' fragments of the second specificity. An anti-CD5/anti-CD20 bsAb was shown to bind targeted antigen either independently or simultaneously. In conclusion, these data show that the three mAbs were all able to induce significant growth inhibition of the JOK1-5.3 cell line in vivo, and efficacy was enhanced when used in combination. IL2/anti-IL-2 complex displayed anti-tumour efficacy in vivo. Further evaluation is necessary to define the most favourable combination to improve mAb therapy. BsAb were produced using the tri-functional agent allowing antibody fragments with relatively good binding. The poor yield obtained with such chemical couplings limited the use of these constructs in preclinical experiments.
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Understanding niche evolution, dynamics, and the response of species to climate change requires knowledge of the determinants of the environmental niche and species range limits. Mean values of climatic variables are often used in such analyses. In contrast, the increasing frequency of climate extremes suggests the importance of understanding their additional influence on range limits. Here, we assess how measures representing climate extremes (i.e., interannual variability in climate parameters) explain and predict spatial patterns of 11 tree species in Switzerland. We find clear, although comparably small, improvement (+20% in adjusted D(2), +8% and +3% in cross-validated True Skill Statistic and area under the receiver operating characteristics curve values) in models that use measures of extremes in addition to means. The primary effect of including information on climate extremes is a correction of local overprediction and underprediction. Our results demonstrate that measures of climate extremes are important for understanding the climatic limits of tree species and assessing species niche characteristics. The inclusion of climate variability likely will improve models of species range limits under future conditions, where changes in mean climate and increased variability are expected.
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Quantifying the impacts of inbreeding and genetic drift on fitness traits in fragmented populations is becoming a major goal in conservation biology. Such impacts occur at different levels and involve different sets of loci. Genetic drift randomly fixes slightly deleterious alleles leading to different fixation load among populations. By contrast, inbreeding depression arises from highly deleterious alleles in segregation within a population and creates variation among individuals. A popular approach is to measure correlations between molecular variation and phenotypic performances. This approach has been mainly used at the individual level to detect inbreeding depression within populations and sometimes at the population level but without consideration about the genetic processes measured. For the first time, we used in this study a molecular approach considering both the interpopulation and intrapopulation level to discriminate the relative importance of inbreeding depression vs. fixation load in isolated and non-fragmented populations of European tree frog (Hyla arborea), complemented with interpopulational crosses. We demonstrated that the positive correlations observed between genetic heterozygosity and larval performances on merged data were mainly caused by co-variations in genetic diversity and fixation load among populations rather than by inbreeding depression and segregating deleterious alleles within populations. Such a method is highly relevant in a conservation perspective because, depending on how populations lose fitness (inbreeding vs. fixation load), specific management actions may be designed to improve the persistence of populations.
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Arenaviruses are a large group of emerging viruses including several causative agents of severe hemorrhagic fevers with high mortality in man. Considering the number of people affected and the currently limited therapeutic options, novel efficacious therapeutics against arenaviruses are urgently needed. Over the past decade, significant advances in knowledge about the basic virology of arenaviruses have been accompanied by the development of novel therapeutics targeting different steps of the arenaviral life cycle. High-throughput, small-molecule screens identified potent and broadly active inhibitors of arenavirus entry that were instrumental for the dissection of unique features of arenavirus fusion. Novel inhibitors of arenavirus replication have been successfully tested in animal models and hold promise for application in humans. Late in the arenavirus life cycle, the proteolytic processing of the arenavirus envelope glycoprotein precursor and cellular factors critically involved virion assembly and budding provide further promising 'druggable' targets for novel therapeutics to combat human arenavirus infection.