Rodents have been reported to play a significant role as reservoirs of over 22 rodent-associated Bartonella species. In this study, we contrast prevalence and diversity of Bartonella infections in 377 small mammals, representative of three terrestrial rodent genera, namely Aethomys, Gerbilliscus and Rhabdomys and one subterranean mole-rat species (Bathyergus suillus). The latter was sampled in close proximity to an informal human settlement, whereas the afore-mentioned murid rodent genera were sampled across a range of landscapes inclusive of natural, agricultural, urban, peri-urban and rural settings, from three provinces (Free State, Gauteng and Western Cape) in South Africa. Molecular estimates of Bartonella infection rates were determined through multi-gene screening of DNA extracted from clinical samples, primarily heart and spleen. PCR assays targeting the citrate synthase (gltA) and NADH dehydrogenase gamma subunit (nuoG) and/or beta subunit of bacterial RNA polymerase (rpoB) genes were used to ensure enhanced molecular estimates of Bartonella prevalence. Aethomys had the highest infection rate (86.7%), whereas Rhabdomys had the lowest (15%). Nucleotide sequencing and phylogenetic analyses revealed that the different primers sets used for Bartonella screening have different affinities to the different strains present in rodents from South Africa. Furthermore, the presence of Bartonella co-infections, confirmed through the presence of multiple peaks at 15% of the nucleotide sequences sites, ranged from 33.8% (in Aethomys) to 42.9% (in Gerbilliscus species) for the gltA gene region. For Aethomys ineptus, of the discrete Bartonella lineages recovered, one was closely related to zoonotic B. elizabethae. The latter species, which is associated with Rattus hosts worldwide and has been linked to cases of human endocarditis, suggests spillover from invasive to indigenous rodents. This is supported by previous studies indicating that indigenous Micaelamys namaquensis, a highly adaptable species, which like Aethomys is capable of utilizing natural and modified landscapes also hosts B. elizabethae-related lineages. Of potential public health importance, Bathyergus suillus were shown to be infected with a zoonotic Bartonella species, B. rochalimae. Our results further indicate that the level of anthropogenic transformation is significantly correlated with Bartonella prevalence, with Rhabdomys sampled from rural settings in the Western Cape Province having infection rates of 36% versus 0% in a nearby urban setting. This study also uncovered high levels of strain diversity in members of the Gerbilliscus cryptic species complex, sampled from an agricultural setting. The overall Bartonella PCR-positivity rate was 67.5 % and the gltA gene phylogeny confirmed the presence of six discrete Bartonella gerbil-specific lineages (I-VI). Lineages I and II clustered with Bartonella strains identified previously in G. leucogaster sampled from Sandveld nature reserves in the Free State Province South Africa, whereas lineages III-VI comprised of lineages that were restricted to either G. leucogaster or to G. brantsii, indicative of host-specificity. From the findings of this study, it is clear that the public health importance of the Bartonella species present in indigenous rodents warrants further investigation as at least two species, with known zoonotic potential (B. elizabethae and B. rochalimae) were shown to be present in rodents sampled in close proximity to human settlements. / Thesis (PhD (Zoology))--University of Pretoria, 2019. / This research was made possible through the financial support from the (AZD-IRT), CDC Co-Ag 5 NU2GGH001874-02-00 and through the NRF incentive and SARChI PI funding awarded to ADSB. / Zoology and Entomology / PhD (Zoology) / Unrestricted

Indiana University-Purdue University Indianapolis (IUPUI) / Assessments of delay discounting in rodent lines bidirectionally selected for home cage intake and preference of alcohol have had mixed findings. The current study sought to examine if delay discounting related differentially to alcohol seeking versus and alcohol drinking, two processes underlying alcohol intake and preference. Three strains of rats were utilized to answer this question Long Evans (LE), high alcohol drinking rats (HAD2), and alcohol preferring P rats. All strains were compared in an adjusting amount delay discounting task. Operant self-administration of alcohol was then assessed in the sipper tube model, and finally home cage drinking was assessed in a 24 hour 2 bottle choice paradigm. In the delay discounting it was found that the P rats were steeper discounters than both the LE and HAD2. In the sipper tube model, P rats displayed higher levels of seeking than both the HAD2s and the LE, but both the P rats and the HAD2s had higher intakes than the LE. During 24 hour home cage access, the P rats and the HAD2s had higher intake and preference for alcohol than the LE, but were not different from each other. These results show that increased discounting of delayed rewards tracks with appetitive processes versus consummatory factors and home cage intake of alcohol. This builds on prior findings using selected line pairs by providing an explanation for discordant results, and supports the hypotheses that increased delay discounting is an intermediate phenotype that predisposes individuals to alcohol use disorders.

No description available.

The Neotropical region is the most biologically diverse region on the planet. The region encompasses a variety of ecosystems and has long been the target of researchers interested in patterns of species diversity and distribution. More recently, molecular data have been incorporated into methods for reconstructing the historical relationships among geographical areas and their biotas. Molecular phylogenetics has provided insights into diversification patterns and the influence of Late Cenozoic events on the evolutionary history of the region. Nevertheless, considering the vast extent and complexity of the region, more studies are needed to fully appreciate the patterns of biogeography and the mechanisms that generate and maintain its biodiversity. Therefore, in Chapter 1 I employed molecular methods to reconstruct the phylogenetic relationships of the subfamily Sigmodontinae, which is the most diverse and widespread radiation of Neotropical rodents. I was able to evaluate controversial hypotheses about the paleogeographic scenarios implicated to explain the biogeography of sigmodontines. Advances in sequencing technology and analytical approaches have revolutionized the role of historical biogeography in elucidating the spatial and temporal context of diversification, and the integrative field of phylogeography was fundamental to the development of biogeography at the intraspecific level. However, the potential of phylogeography to unravel diverse historical scenarios in a tractable statistical framework has been largely unexplored for the Neotropics as a whole. In order to integrate more robust hypothesis testing to elucidate the evolutionary history of Amazonia's biota, I devoted Chapter 2 to a review of Amazonian phylogeography that I anticipate will improve the basis for interpreting the patterns and processes of diversification in Amazonia. Chapter 3 is a thorough species account of spiny rats of the genus Proechimys, which is poorly known taxonomically despite its diversity and widespread distribution in the Neotropics. This taxonomic revision will benefit researchers interested in using such information with coalescent-based methods of species delimitation aimed at an integrative and stable taxonomy. Lastly, Chapter 4 deals with the phylogeography of P. roberti. This species occurs in southeastern Amazonia and the Cerrado of central Brazil. I employed a dense taxon sampling and used coalescent-based methods to demonstrate that rivers and topography have a causal link to the geographic structure of P. roberti populations. In my dissertation, I used a combination of molecular genetics tools to provide a better understanding of the biogeography and evolution of some of the most diverse groups of Neotropical mammals. My dissertation interacts in many levels with my future research interests. These present and future efforts hold promise for unraveling the evolutionary history of the Neotropical region and its biota, and will assist in conservation decisions aiming at preserving its unparalleled biodiversity.

No description available.

[pt] A dor é uma desagradável experiência sensorial, emocional e subjetiva, podendo ou não estar associada a um dano tecidual, sendo possível dividi-la em 3 categorias: em dor nociceptiva, inflamatória, e patológica, esta podendo ser neuropática ou disfuncional. A dor neuropática irá aparecer após uma lesão nervosa, ou até mesmo por uma doença no sistema nervoso incluindo as fibras periféricas e neurônios centrais. Essas lesões e doenças podem levar à transmissão alterada e desordenada de sinais sensoriais na medula espinhal e no cérebro. Foi relatado que emoções negativas acabam exacerbando a dor crônica, o que resulta em doenças refratárias. Uma ampla variedade de áreas no cérebro constitui a matriz da dor, essas regiões são ativadas durante a codificação da localização, intensidade, duração, qualidade e associações emocionais da dor nociceptiva, e vai mostrar como a dor pode ser influenciada pelo humor. Diversas evidências apontam que a dor crônica compartilha muitas características com doenças neurodegenerativas, incluindo o desenvolvimento da depressão maior e ansiedade. Experimentos de dor usando seres humanos são bastante desafiadores, subjetivos e eticamente autolimitados, assim, quando o intuito é entender melhor os mecanismos da dor, modelos animais são mais amplamente utilizados. Os modelos animais oferecem uma vantagem no que diz respeito a padronização de antecedentes genéticos e ambientais, sem contar na economia e segurança que esses estudos proporcionam. O modelo do spared nerve injury (SNI), é um modelo clássico animal para dor que irá exibir manifestações comportamentais típicas de dor neuropática. Provou ser um método efetivo que mostrou substancialmente e de maneira prolongada as mudanças sensitivas, mecânicas e termais nas respostas que imitam de maneira bem próxima as configuradas na dor neuropática clínica. Este trabalho, portanto, trata-se de uma revisão sistemática de caráter descritivo. A coleta de artigos foi realizada por meio de um levantamento bibliográfico na base de dados PubMed, Web of Science e Embase. Com os critérios de inclusão sendo estudos experimentais; modelos animais de dor (camundongos e ratos), mais especificamente o modelo de spared nerve injury (SNI), e medições do comportamento tipo ansioso através de testes comportamentais. Com base nesses critérios, de 21 artigos elegíveis, foram incluídos 18 resultados. Pesquisas em ratos e camundongos mostraram que alguns dias após o SNI, os animais apresentaram dor neuropática e comportamento semelhante à ansiedade. E alguns estudos apresentaram intervenções capazes de atenuar tanto a dor neuropática quanto o comportamento do tipo ansioso. A administração de oral 2-OHOA teve potencial analgésico, além de reduzir a ansiedade comportamental, a administração oral do óleo essencial de Ylang-ylang (YEO) em doses analgésicas aumenta o limiar da dor, tem efeito ansiolítico relacionado à ansiedade, uma dose baixa de o paracetamol reduziu os danos nos nervos associados à ansiedade, tratando o núcleo amigdaloide central com tetrapentilamônio (TPA), atenuou o desenvolvimento de dor neuropática e comportamento semelhante à ansiedade, os receptores 5HT1 foram necessários para o efeito ansiolítico do Canabidiol (CBD), o UR13870 oral teve potencial analgésico, além de reduzir a ansiedade comórbida, o ambiente enriquecido reduziu o comportamento ansioso e depressivo na adolescência, a inibição do P2X7R, pode melhorar os sintomas de dor e o P2X7ko teve potencial para prevenir o comportamento semelhante à ansiedade, a administração de elemene reduziu a dor neuropática e demonstrou reduzir comportamento semelhante à ansiedade. O comportamento semelhante à ansiedade foi suprimido pela aplicação local de serotonina no córtex pré-frontal medial. A eletroacupuntura e a inibição específica da via rACCGlu-vlPAG podem aliviar comportamentos semelhantes à ansiedade. Temos então a micróglia como um alvo bastante promissor para futuras medidas terapêuticas, mostrando que é possível amenizar a dor e o comportamento tipo ansioso em casos de lesões do nervo periférico, através da sua inibição. / [en] Pain is a sensory, emotional and subjective experience, which may or may not be associated with tissue damage, being possible to divide it into 3 categories: nociceptive, inflammatory, and pathological pain, which may be neuropathic or dysfunctional. Neuropathic pain will appear after a nervous injury, or even due to a disease in the nervous system, including peripheral fibers (Abeta, Adelta and C) and central neurons. These injuries and diseases can lead to altered and disordered transmission of sensory signals in the spinal cord and brain. Negative emotions have been reported to exacerbate chronic pain, resulting in refractory disease. A wide variety of areas in the brain can be constituted as the pain matrix, these regions are activated during concentration on the location, intensity, duration, quality and emotional associations of nociceptive pain, and will show how pain can be influenced by mood. And several evidences indicate that chronic pain shares many characteristics with neurodegenerative diseases, including the development of major depression and anxiety, with anxiety disorders being one of the most prevalent psychiatric conditions nowadays. Pain experiments using human subjects are quite challenging, subjective and ethically self-limiting, so when the aim is to better understand pain mechanisms, animal models are more widely used, offering an advantage over human studies in terms of standardizing genetic and environmental backgrounds. The spared nerve injury (SNI) model is a classic animal model for pain that will exhibit typical behavioral manifestations of neuropathic pain. It proved to be an effective method that showed substantial and prolonged sensory, mechanical and thermal changes in responses that closely mimic those configured in clinical neuropathic pain. This work, therefore, is a systematic review of a descriptive nature. A systematic search was conducted in MEDLINE/PubMed, Embase and Web of Science, and was performed according to PRISMA guidelines. The inclusion criteria was mainly the mention of neuropathic pain, an anxiety disorder and the spared nerve injury model in the same study. Quality of studies was evaluated according to the table of risk of bias from SYRCLE. From 21 eligible studies, 18 were included. Research in rats and mice shows that a few days after the SNI, the animals presented both neuropathic pain and anxiety-like behavior. And some studies presented interventions that were able to attenuate both neuropathic pain and the anxiety-like behavior. The administration of 2-OHOA had analgesic potential, in addition to reducing behavioral anxiety associated with SNI, the Ylang-ylang essential oil (YEO) in analgesic doses increases the pain threshold, has an anxiolytic effect related to the anxiety, a low dose of paracetamol reduced nerve damage associated with anxiety, treating the central amygdaloid nucleus with tetrapentylammonium (TPA), attenuated the development of neuropathic pain and anxiety-like behavior, 5HT1 receptors were necessary for the anxiolytic effect of Cannabidiol (CBD), UR13870 had analgesic potential in SNI, in addition to reducing comorbid anxiety, enriched environment reduced anxious and depressive behavior in adolescence, the inhibition of P2X7R, could improve pain symptoms, and P2X7ko had potential to prevent anxiety-like behavior, elemene administration reduced neuropathic pain and was shown to reduce anxiety-like behavior, Anxiety-like behavior was suppressed by local application of serotonin to the medial prefrontal córtex. Electroacupuncture and specific inhibition of the rACCGlu-vlPAG pathway can alleviate anxiety-like behaviors.

Three desert Artemisia tridentata communities in Rush Valley, Utah were trapped for small rodents during the summer of 1970 in a mark-recapture study. Population densities were estimated using several indices for each population category. Animals were weighed and rodent biomass calculated for each species throughout the summer. Populations, biomass, and other data were then analyzed to gain a better understanding of A. tridentata community types of the Great Basin. Peromyscus maniculatus, Eutamias minimus, and Reithrodontomys megalotis were common to area 1. Peromyscus maniculatus, E. minimus, and Perognathus parvus were common to areas 2 and 3. The peak estimated standing crops were 182.8, 143.1, and 129.7 g/acre for areas 2, 1, and 3 respectively. The population and biomass of area 2 peaked in mid-summer, area 1 in early summer, and area 3 in late summer. Results from a similar study indicate mountain A. tridentata communities may be less productive, in terms of rodent biomass, than desert A. tridentata communities at lower elevations.

Information concerning the mammals of Zion National Park was needed for management purposes and general information. During the summers of 1975 and 1976, mammals observed throughout the park were recorded and habitat structure was measured for each animal at the immediate observation site. Ordinations based on stepwise discriminant analyses of the data on 12 rodent species were constructed and substantiated by Bray-Curtis analyses. The results showed that amounts of cover and boulders contrasted the habitats of Peromyscus eremicus, P. maniculatus, P. crinitus, P. boylii and P. truei. A second group of species--Eutamias minimus, E. umbrinus, Spermophilus variegatus, Tamiasciurus hudsonicus, Dipodomys merriami, Neotoma lepida and Microtus longicaudus--were discriminated by amounts of litter, grass and trees in the habitat of each species. A list of mammalian species found within Zion and suggestions for further study are given.

L'anesthésie générale est associée à une altération significative de la thermorégulation normale. L'augmentation de température cutanée avec pré-réchauffement réduit la redistribution durant l'anesthésie. Les principaux objectifs étaient: 1) étudier l'efficacité de stratégies de pré-réchauffement pendant l'anesthésie; 2) comparer l'efficacité du réchauffement actif au réchauffement passif et 3) évaluer l'efficacité du pré-réchauffement pour prévenir l'hypothermie après prémédication intramusculaire. Dans une étude prospective, croisée de 17 rats adultes, trois stratégies de préchauffage ont été évaluées : PW1% (augmentation température de 1%), PW40 (augmentation à 40°C) et NW (pas de réchauffement). Le pré-réchauffement a efficacement retardé l'atteinte du seuil d’hypothermie (7.1 minutes pour le groupe NW vs 12.4 minutes et 19.3 minutes pour PW1% et PW40, respectivement). Ces temps étaient significativement différents entre groupes: PW1% vs PW40 (p = 0.0044 (95% CI -12 à -2.2), PW40 vs NW (p < 0.0001 (95%CI 8.1 à 16.0) et PW1% vs NW (p = 0.003, 95%CI 1.8 à 8.7). Dans une étude prospective, randomisée, croisée et expérimentale sur 8 rats, le réchauffement actif (coussin chauffant) a été comparé au réchauffement passif (couverture) après pré-réchauffement (augmentation température centrale de 1%). La température a été maintenue plus adéquatement dans le groupe actif pendant (P = 0,008 [95%CI 3,2 à 20,4]) et après l'anesthésie (P = 0,002 [95%CI 4,2 à 17,7]). Dans une étude prospective, randomisée, croisée, une sédation intramusculaire (kétamine-midazolam-hydromorphone) a été administrée à 8 rats suivi d’une période de 14 minutes en cage non chauffée ou boîte chauffée. Une période d’anesthésie de 30 minutes avec soutien thermique a suivi. Au début du réveil, les rats chauffés avaient une température plus élevée (2/8 rats hypothermiques vs 6/8 rats non chauffés (P < 0.0001)) / General anesthesia is associated with a significant alteration of normal thermoregulation. Increasing skin temperature with pre-warming reduces heat redistribution during anesthesia. The main objectives were: 1) to study the effectiveness of prewarming strategies during anesthesia; 2) to compare the effectiveness of active versus passive warming; and 3) to evaluate the effectiveness of prewarming in preventing hypothermia after intramuscular premedication. In a prospective, crossover study of 17 adult rats, three prewarming strategies were evaluated: PW1% (1% temperature increase), PW40 (increase to 40°C), and NW (no warming). Pre-warming effectively delayed reaching hypothermia threshold (7.1 minutes for the NW group, compared to 12.4 minutes and 19.3 minutes for the PW1% and PW40 groups, respectively). These times were significantly different between groups: PW1% vs PW40 (p = 0.0044 (95%CI -12 to -2.2), PW40 vs NW (p < 0.0001 (95%CI 8.1 to 16.0) and PW1% vs NW (p = 0.003, 95%CI 1.8 to 8.7). In a prospective, randomized, crossover, experimental study of 8 rats, active warming (heating pad) was compared with passive warming (blanket) after pre-warming (1% core temperature increase). Temperature was more adequately maintained in the active group during (P = 0.008 [95%CI 3.2 to 20.4]) and after anesthesia (P = 0.002 [95%CI 4.2 to 17.7]). In a prospective, randomized, crossover study, intramuscular sedation (ketamine-midazolam-hydromorphone) was administered to 8 rats followed by a 14-minute period in an unheated cage or heated box. A 30-minute period of anesthesia with thermal support followed. At the onset of awakening, heated rats had a higher temperature (2/8 hypothermic rats vs 6/8 unheated rats (P < 0.0001))

<p>Pre-clinical imaging has provided pulmonary researchers with a number of valuable tools for studying both the lung and lung disease. A greater understanding of the structure/function relationships within the rodent lung would help to bridge the gap between functional images of the lung and its underlying anatomy.</p> <p>The objectives of this work were to visualize and measure the components of rodent lung anatomy. Contrast-enhanced microCT images were used to visualize the airways and major blood vessels from both the Sprague-Dawley rat and the BALB/c mouse. These observations and measurements were used in the development of a pulmonary lung model containing both the conducting airways and blood vessels. The model can be applied to unenhanced images of the rodent lung to facilitate the regionalization of functional imaging data (SPECT/PET). The model has been used to simulate bronchoconstriction and deposition patterns of inhaled particles. Extensive validation revealed that the model was unable to fully reproduce the rodent lung and that further refinement is necessary.</p> <p>The finer structure of the rodent lung, which could not be resolved using our microCT system, was measured using histological sections of the rodent lung. Software was developed and validated to automatically quantify the increases in airspace size that are associated with several respiratory conditions.</p> <p>Together, this work sheds light on the underlying anatomy of the rodent lung that is present in both anatomical and functional images. The knowledge will help researchers to understand some of the structural changes that are occurring with the development of lung disease.</p> / Doctor of Philosophy (PhD)