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Tissier Mathilde - One of the best experts on this subject based on the ideXlab platform.
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Captive-reared European Hamsters follow an offensive strategy during risk-assessment
'Public Library of Science (PLoS)', 2019Co-Authors: Tissier Mathilde, Bousquet Christophe, Fleitz Julie, Habold Caroline, Petit Odile, Handrich YvesAbstract:International audienceUnderstanding whether captive-reared animals destined to reintroduction are still able to discriminate predators has important implications for conservation biology. The endangered European hamster benefits from conservation programs throughout Europe, in which several thousand individuals are released into the wild every year. Despite this, the anti-predator strategy of Hamsters and their ability to maintain predator discrimination in captivity remain to be investigated. Here, we explore the predator discrimination behaviour of captive-reared European Hamsters and their response to different predation cues. When first exposed to the urine of cats and goats in a Y-maze test, Hamsters spent more time close to the cat scent rather than to the goat scent. In a second experiment, during which Hamsters were exposed to a non-mobile European ferret (inside a cage), Hamsters significantly increased the time spent close to the ferret's cage and displayed aggressive behaviour towards the ferret. Furthermore, they did not take refuge inside an anti-predation tube (APT), a device designed to upgrade wildlife underpasses and reconnect wild hamster populations. Finally, when exposed to a mobile ferret (but without physical contact), Hamsters displayed mobbing and aggressive behaviours towards the ferret, before taking refuge inside the APT. Taken together, our results show that captive-reared Hamsters are still able to detect and react to predation cues, but that they initially adopt an offensive strategy (grunting, spitting, mobbing) during the risk-assessment phase. After risk assessment, however, Hamsters used the APT as a refuge. Our study provides important insights into the anti-predator behaviour of Hamsters. Testing the efficacy of the APT, a device that will allow upgrading wildlife underpasses for the hamster and other rodents, is also of great importance and is instrumental in conservation efforts for these species
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Conservation du Grand hamster (Cricetus cricetus) : effets nutritionnels des cultures céréalières sur la fitness de l'espèce et reconnexion des populations à travers la mise en place de systèmes anti-prédation
HAL CCSD, 2017Co-Authors: Tissier MathildeAbstract:The European hamster (Cricetus cricetus), one of the most endangered mammal in Europe, is on the verge of extinction in France. However, we are still lacking information on the causes of its decline and on how to improve its conservation. During my PhD, I therefore investigated for the nutritional effects of crops on Hamsters’ fitness. The main results highlight that elevated maize consumption is severely reducing Hamsters’ reproduction because of a major deficiency in vitamin B3. Then, I found that crop associations such as wheat-soybean and maize-sunflower are favorable to the species and should be implemented in the Alsace. I also developed an anti-predation tube (APT) that will serve to upgrade wildlife underpasses and ultimately allow to reconnect wild populations. Moreover, behavioral tests presented in this thesis reveal that Hamsters display bold behaviors when facing a predator. Nonetheless, they use the APT as a refuge in such cases, which validated its anti-predatory function. Therefore, the APT will now be implemented in wildlife underpasses in the Alsace. Results of this PhD will now benefit the conservation of the species in France and in Europe.Le Grand hamster (Cricetus cricetus), l’un des mammifères les plus menacés d’Europe, est en voie d’extinction en France. Toutefois, nous manquons d’information sur les causes de son déclin et sur comment améliorer sa conservation. Durant ma thèse, je me suis intéressée à l’effet des cultures sur la reproduction du hamster. Les principaux résultats indiquent qu’une consommation importante de maïs conduit à une diminution drastique du succès reproducteur en raison d’une carence en vitamine B3. Une autre étude démontre que des associations de cultures (blé-soja ou maïs-tournesol) sont favorables au hamster et devraient être mises en place en Alsace. En parallèle, j’ai développé un tube anti-prédation (TAP) pour améliorer les passages à faune et reconnecter les populations sauvages. Des tests comportementaux ont révélé que les Hamsters présentent des comportements audacieux face au prédateur, mais utilisent tout de même le TAP comme refuge, validant sa fonction anti-prédation. Le TAP sera maintenant mis en place dans plusieurs passages à faune en Alsace. Les résultats de cette thèse vont maintenant bénéficier à la conservation du hamster en France et en Europe
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Conservation du Grand hamster (Cricetus cricetus): Effets nutritionnels des cultures céréalières sur la fitness de l’espèce et reconnexion des populations à travers la mise en place de systèmes anti-prédation.
HAL CCSD, 2017Co-Authors: Tissier MathildeAbstract:IPHC, Département d'Ecologie, Physiologie et Ethologie (UMR7178)The European hamster (Cricetus cricetus) is one of the most endangered mammal in Europe. In France, lessthan 800 individuals are currently inhabiting farmlands of the ‘Grand-Est’ Region. However, despite thespecific actions undertaken since 2000 in favor of Hamsters’ conservation, the French population is stillhighly threatened. My thesis is part of the project ALISTER (Life + Biodiversity program funded by theEuropean Union), which aims at testing the relevance (at the regional level) of some actions previouslyidentified as potentially favorable to the species. Nonetheless, there is still a huge gap in understanding theunderlying mechanisms that could affect Hamsters’ fitness. Specifically, this work therefore aimed atbringing scientific knowledge regarding Hamsters’ eco-physiology and behavioral ecology, in order toimprove conservation strategies of this targeted species. This has been done throughout two mainapproaches:1. Investigating for the nutritional effects of crops on the fitness of the hamster and finding which crops, ofeconomic interest, are the most favorable for the hamster in terms of nutritional inputs. In that aim, theeffects of several crops on the hibernation and the reproductive success of captive and semi-captiveHamsters have been investigated. The main results highlight that elevated maize consumption is severelyreducing Hamsters’ reproduction because of a major deficiency in vitamin B3. This deficiency appearsextremely difficult to compensate with other food items, and only the association with sunflower allowHamsters to have a proper hibernation and first reproduction under captive conditions. More broadly,results highlight the negative effects of wheat and maize monoculture on the fitness of this species andpinpoint that the implementation of crop associations such as wheat-soybean and maize-sunflower needto be implemented in the Alsace, as a conservation measure for this species.2. Evaluating the antipredatory behavior of the European hamster and developing an anti-predation tube(APT) that will serve to upgrade wildlife underpasses in the Alsace and ultimately allow to reconnect wildpopulations. The tests have been carried out under controlled and semi-captive conditions and the mainresults reveal that Hamsters display an offensive strategy (e.g. mobbing, threatening and attacking thepredator) when facing cats’ urine or a real predator (i.e. the European ferret). In these context, the efficiencyof our anti-predation device has been validated since it allowed hamster to take refuge when facing anactual predation risk. The APT will now be implemented in wildlife underpasses in the Alsace, whereas itseffectiveness will now be evaluated via a comprehensive video monitoring under natural conditions. Theresults obtained regarding the antipredatory behavior of this species bring new perspective avenues thatcould be applied to the hamster conservation.Le Grand hamster (Cricetus cricetus), l’un des mammifères les plus menacés d’Europe, est en voie d’extinctionen France. Toutefois, nous manquons d’information sur les causes de son déclin et sur comment améliorer saconservation. Durant ma thèse, je me suis intéressée à l’effet des cultures sur la reproduction du hamster. Lesprincipaux résultats indiquent qu’une consommation importante de maïs conduit à une diminution drastiquedu succès reproducteur en raison d’une carence en vitamine B3. Une autre étude démontre que desassociations de cultures (blé-soja ou maïs-tournesol) sont favorables au hamster et devraient être mises enplace en Alsace. En parallèle, j’ai développé un tube anti-prédation (TAP) pour améliorer les passages à fauneet reconnecter les populations sauvages. Des tests comportementaux ont révélé que les Hamsters présententdes comportements audacieux face au prédateur, mais utilisent tout de même le TAP comme refuge, validantsa fonction anti-prédation. Le TAP sera maintenant mis en place dans plusieurs passages à faune en Alsace. Lesrésultats de cette thèse vont maintenant bénéficier à la conservation du hamster en France et en Europe
William S. M. Wold - One of the best experts on this subject based on the ideXlab platform.
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16 stat2 knockout syrian Hamsters support enhanced replication and pathogenicity of human adenovirus type 5 revealing an important role of type i interferon response in viral control
Molecular Therapy, 2016Co-Authors: Karoly Toth, Jacqueline F. Spencer, Ann E. Tollefson, Baoling Ying, Zhongde Wang, John E Sagartz, Ilkeun Kong, William S. M. WoldAbstract:Oncolytic vectors based on human species C adenovirus type 5 (Ad5) are being developed for cancer gene therapy. Studies on wild-type Ad5 in animal models are likely to provide important insights into the behavior of these vectors in patients. The most frequently used permissive immunocompetent animal model for Ad5 infection is the Syrian hamster. Ad5 (and Ad6) replicates in these animals and causes pathology that is similar to that seen with humans. Here, we report findings with a new Syrian hamster strain in which the STAT2 gene was functionally knocked out (KO) by site-specific CRISPR/Cas9-mediated gene targeting. STAT2 is a critical element of the Type I and Type III interferon signal transduction pathways. STAT2 KO Hamsters infected intravenously with Ad5 demonstrated an accentuated pathology compared to the wild-type control animals, and the virus load in the organs (liver, lung, kidney) of STAT2 KO animals was 100- to 1000-fold higher than that in wild-type Hamsters. We show that the Type I interferon pathway is disrupted in these Hamsters, inasmuch as the interferon response genes PKR, OAS, and Mx2 were induced by Ad5 in the liver of wild-type but not STAT2 KO Hamsters, revealing a critical role of interferon-stimulated genes in controlling Ad5 infection. Notably, the adaptive immune response to Ad5 is not adversely affected in STAT2 KO Hamsters, and surviving Hamsters cleared the infection by 7 to 10 days post challenge. In fact, anti-Ad5 neutralizing antibodies were 10-fold higher at 7 days postinfection in the STAT2 KO Hamsters than in wild-type Hamsters. T cell infiltration into the liver was similar at 3 and 7 days in the STAT2 KO and wild-type Hamsters. Treatment of Ad5-infected STAT2 KO Hamsters with high dose cyclophosphamide resulted in markedly increased mortality, pathogenesis, and virus replication in the liver (~1011 TCID50/g liver) at 10 days postinfection, likely because the adaptive immune response as well as other aspects of the innate response were abolished. This is the first study to report findings with a genetically modified Syrian hamster infected with human adenovirus. Further, this is the first study to show that the Type I interferon pathway plays a role in inhibiting Ad5 replication in a permissive animal model. This conclusion is in accord with a previous study in which we showed using a custom microarray platform that there is a robust up-regulation of genes involved in the innate immune response (e.g. OAS, PKR, IFN-inducible protein 10) in the liver at 18 h post-intravenous infection of wild-type Syrian Hamsters with Ad5 (Ying, B. et al., Virology 485, 305, 2015). Besides providing an insight into adenovirus infection in humans, our results underscore the usefulness of Syrian Hamsters as a permissive model for the study of species C human adenovirus and adenovirus-based vectors. In future studies, STAT2 KO Hamsters bearing tumors could be used to explore the role of Type I and Type III interferon signaling on the efficacy of oncolytic adenovirus vectors.
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stat2 knockout syrian Hamsters support enhanced replication and pathogenicity of human adenovirus revealing an important role of type i interferon response in viral control
PLOS Pathogens, 2015Co-Authors: Karoly Toth, Jacqueline F. Spencer, Ann E. Tollefson, Baoling Ying, Zhongde Wang, John E Sagartz, Ilkeun Kong, William S. M. WoldAbstract:Human adenoviruses have been studied extensively in cell culture and have been a model for studies in molecular, cellular, and medical biology. However, much less is known about adenovirus replication and pathogenesis in vivo in a permissive host because of the lack of an adequate animal model. Presently, the most frequently used permissive immunocompetent animal model for human adenovirus infection is the Syrian hamster. Species C human adenoviruses replicate in these animals and cause pathology that is similar to that seen with humans. Here, we report findings with a new Syrian hamster strain in which the STAT2 gene was functionally knocked out by site-specific gene targeting. Adenovirus-infected STAT2 knockout Hamsters demonstrated an accentuated pathology compared to the wild-type control animals, and the virus load in the organs of STAT2 knockout animals was 100- to 1000-fold higher than that in wild-type Hamsters. Notably, the adaptive immune response to adenovirus is not adversely affected in STAT2 knockout Hamsters, and surviving Hamsters cleared the infection by 7 to 10 days post challenge. We show that the Type I interferon pathway is disrupted in these Hamsters, revealing the critical role of interferon-stimulated genes in controlling adenovirus infection. This is the first study to report findings with a genetically modified Syrian hamster infected with a virus. Further, this is the first study to show that the Type I interferon pathway plays a role in inhibiting human adenovirus replication in a permissive animal model. Besides providing an insight into adenovirus infection in humans, our results are also interesting from the perspective of the animal model: STAT2 knockout Syrian hamster may also be an important animal model for studying other viral infections, including Ebola-, hanta-, and dengue viruses, where Type I interferon-mediated innate immunity prevents wild type Hamsters from being effectively infected to be used as animal models.
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use of the syrian hamster as an animal model for oncolytic adenovirus vectors
Methods in molecular medicine, 2007Co-Authors: Maria A. Thomas, Jacqueline F. Spencer, William S. M. WoldAbstract:Oncolytic adenoviruses (Ads) are promising candidates for cancer therapy. However, current animal models to evaluate these vectors have substantial limitations. Because Ad replication is generally species-specific, oncolytic Ads are usually examined in immunodeficient mice bearing human xenograft tumors. However, this model suffers because the animals are immunodeficient and normal and cancerous mouse tissues are poorly permissive to human Ad replication. We have recently developed a Syrian hamster model that is both immunocompetent and permissive to human Ad replication in normal and cancerous tissues. The Syrian hamster is also permissive for Ad5 replication in the lung, which is the natural site of infection in humans. Human Ads replicate well in vitro in the Syrian hamster cell lines examined and demonstrate significant antitumor efficacy following injection into Syrian hamster tumors in vivo. In this chapter we describe the maintenance of these Syrian hamster cell lines in culture and how to assess oncolytic Ad vector replication in these cells in vitro. We also describe detailed methods for growth of these cell lines as subcutaneous tumors, for intravenous and intratumoral injections in Hamsters, and for evaluation of the efficacy, replication, and biodistribution of oncolytic Ad vectors following administration in Hamsters. In addition, we describe how to assess replication in normal tissues such as the lungs and give helpful tips on handling, anesthesia, and general care of Syrian Hamsters.
Radhakrishnan Murali Naidu - One of the best experts on this subject based on the ideXlab platform.
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Chemopreventive potential of esculetin in 7,12-dimethylbenz(a)anthracene-induced hamster buccal pouch carcinogenesis
Molecular and Cellular Biochemistry, 2018Co-Authors: Renganathan Selvasundaram, Rajamanickam Buddhan, Mani Neelakandan, Radhakrishnan Murali NaiduAbstract:7,12-Dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch carcinogenesis is widely preferred to assess the tumor-inhibiting efficacy of the medicinal plants or their constituents. The present study explores the tumor-inhibiting potential of esculetin by utilizing the status of lipid peroxidation by products (thiobarbituric acid reactive substances), antioxidants (vitamin E, reduced glutathione, superoxide dismutase, catalase, and glutathione peroxidase), and phase I and phase II detoxification agents as biochemical end points and by using histopathological studies as well in DMBA-induced hamster buccal pouch carcinogenesis. Oral tumors developed in the buccal pouch were subjected to histopathological studies, and were confirmed as oral squamous cell carcinoma. Hamsters treated with DMBA alone showed an abnormal pattern of lipid peroxidation, antioxidants, and detoxification agents as compared to control Hamsters. The status of the above-mentioned biochemical markers and histopathological abnormalities were found to be reversed in DMBA + esculetin-treated Hamsters. The result of the present study thus indicates the tumor preventive potential of esculetin in DMBA-induced oral carcinogenesis.
Karoly Toth - One of the best experts on this subject based on the ideXlab platform.
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16 stat2 knockout syrian Hamsters support enhanced replication and pathogenicity of human adenovirus type 5 revealing an important role of type i interferon response in viral control
Molecular Therapy, 2016Co-Authors: Karoly Toth, Jacqueline F. Spencer, Ann E. Tollefson, Baoling Ying, Zhongde Wang, John E Sagartz, Ilkeun Kong, William S. M. WoldAbstract:Oncolytic vectors based on human species C adenovirus type 5 (Ad5) are being developed for cancer gene therapy. Studies on wild-type Ad5 in animal models are likely to provide important insights into the behavior of these vectors in patients. The most frequently used permissive immunocompetent animal model for Ad5 infection is the Syrian hamster. Ad5 (and Ad6) replicates in these animals and causes pathology that is similar to that seen with humans. Here, we report findings with a new Syrian hamster strain in which the STAT2 gene was functionally knocked out (KO) by site-specific CRISPR/Cas9-mediated gene targeting. STAT2 is a critical element of the Type I and Type III interferon signal transduction pathways. STAT2 KO Hamsters infected intravenously with Ad5 demonstrated an accentuated pathology compared to the wild-type control animals, and the virus load in the organs (liver, lung, kidney) of STAT2 KO animals was 100- to 1000-fold higher than that in wild-type Hamsters. We show that the Type I interferon pathway is disrupted in these Hamsters, inasmuch as the interferon response genes PKR, OAS, and Mx2 were induced by Ad5 in the liver of wild-type but not STAT2 KO Hamsters, revealing a critical role of interferon-stimulated genes in controlling Ad5 infection. Notably, the adaptive immune response to Ad5 is not adversely affected in STAT2 KO Hamsters, and surviving Hamsters cleared the infection by 7 to 10 days post challenge. In fact, anti-Ad5 neutralizing antibodies were 10-fold higher at 7 days postinfection in the STAT2 KO Hamsters than in wild-type Hamsters. T cell infiltration into the liver was similar at 3 and 7 days in the STAT2 KO and wild-type Hamsters. Treatment of Ad5-infected STAT2 KO Hamsters with high dose cyclophosphamide resulted in markedly increased mortality, pathogenesis, and virus replication in the liver (~1011 TCID50/g liver) at 10 days postinfection, likely because the adaptive immune response as well as other aspects of the innate response were abolished. This is the first study to report findings with a genetically modified Syrian hamster infected with human adenovirus. Further, this is the first study to show that the Type I interferon pathway plays a role in inhibiting Ad5 replication in a permissive animal model. This conclusion is in accord with a previous study in which we showed using a custom microarray platform that there is a robust up-regulation of genes involved in the innate immune response (e.g. OAS, PKR, IFN-inducible protein 10) in the liver at 18 h post-intravenous infection of wild-type Syrian Hamsters with Ad5 (Ying, B. et al., Virology 485, 305, 2015). Besides providing an insight into adenovirus infection in humans, our results underscore the usefulness of Syrian Hamsters as a permissive model for the study of species C human adenovirus and adenovirus-based vectors. In future studies, STAT2 KO Hamsters bearing tumors could be used to explore the role of Type I and Type III interferon signaling on the efficacy of oncolytic adenovirus vectors.
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stat2 knockout syrian Hamsters support enhanced replication and pathogenicity of human adenovirus revealing an important role of type i interferon response in viral control
PLOS Pathogens, 2015Co-Authors: Karoly Toth, Jacqueline F. Spencer, Ann E. Tollefson, Baoling Ying, Zhongde Wang, John E Sagartz, Ilkeun Kong, William S. M. WoldAbstract:Human adenoviruses have been studied extensively in cell culture and have been a model for studies in molecular, cellular, and medical biology. However, much less is known about adenovirus replication and pathogenesis in vivo in a permissive host because of the lack of an adequate animal model. Presently, the most frequently used permissive immunocompetent animal model for human adenovirus infection is the Syrian hamster. Species C human adenoviruses replicate in these animals and cause pathology that is similar to that seen with humans. Here, we report findings with a new Syrian hamster strain in which the STAT2 gene was functionally knocked out by site-specific gene targeting. Adenovirus-infected STAT2 knockout Hamsters demonstrated an accentuated pathology compared to the wild-type control animals, and the virus load in the organs of STAT2 knockout animals was 100- to 1000-fold higher than that in wild-type Hamsters. Notably, the adaptive immune response to adenovirus is not adversely affected in STAT2 knockout Hamsters, and surviving Hamsters cleared the infection by 7 to 10 days post challenge. We show that the Type I interferon pathway is disrupted in these Hamsters, revealing the critical role of interferon-stimulated genes in controlling adenovirus infection. This is the first study to report findings with a genetically modified Syrian hamster infected with a virus. Further, this is the first study to show that the Type I interferon pathway plays a role in inhibiting human adenovirus replication in a permissive animal model. Besides providing an insight into adenovirus infection in humans, our results are also interesting from the perspective of the animal model: STAT2 knockout Syrian hamster may also be an important animal model for studying other viral infections, including Ebola-, hanta-, and dengue viruses, where Type I interferon-mediated innate immunity prevents wild type Hamsters from being effectively infected to be used as animal models.
S Nagini - One of the best experts on this subject based on the ideXlab platform.
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s allylcysteine a garlic constituent inhibits 7 12 dimethylbenz a anthracene induced hamster buccal pouch carcinogenesis
Nutrition and Cancer, 2001Co-Authors: Seetharaman Balasenthil, C R Ramachandran, S NaginiAbstract:The effect of S-allylcysteine (SAC), a water-soluble garlic constituent, on 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis was investigated in male Syrian hamstes. Forty Hamsters were divided into 4 groups of 10 animals. The right buccal pouches of the animals in Group I were painted with a 0.5% solution of DMBA in liquid paraffin three times a week. The animals in Group II were painted with DMBA as in Group I and, in addition, received 200 mg/kg body wt p.o. SAC three times a week on days alternate to DMBA application. Group III animals received SAC as in Group II. Group IV animals received neither DMBA nor SAC and served as the control. The Hamsters were killed after an experimental period of 14 wk. Measurement of lipid peroxidation, the antioxidant enzymes superoxide dismutase (SOD) and catalase, in the buccal pouch mucosa, liver, and circulation was used to monitor the chemopreventive potential of SAC. All Hamsters painted with DMBA alone developed tumors identified histologically as well-differentiated squamous cell carcinomas. In Hamsters bearing DMBA-induced buccal pouch tumors, diminished lipid peroxidation in the tumor tissue was accompanied by decreased activities of SOD and catalase, whereas in the liver and circulation, enhanced lipid peroxidation was associated with compromised antioxidant defenses. Administration of SAC suppressed the incidence of DMBA-induced HBP tumors as revealed by the absence of carcinomas. Histologically, only keratosis was observed. SAC modulated DMBA-induced decreased susceptibility of the HBP to lipid peroxidation while simultaneously enhancing SOD and catalase activities, whereas in the liver and circulation, SAC decreased the extent of lipid peroxidation and significantly enhanced antioxidant activities. We suggest that SAC exerts its chemopreventive effects by modulating lipid peroxidation and enhancing antioxidant activities in the target organ as well as in the liver and circulation.
