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Sample records for tropical rodent funambulus

  1. Photoperiodic regulation of nuclear melatonin receptor RORα in lymphoid organs of a tropical rodent Funambulus pennanti: role in seasonal oxidative stress.

    PubMed

    Gupta, Sameer; Haldar, Chandana; Ahmad, Raise

    2015-01-01

    The orphan nuclear receptor RORα of RZR/ROR family has been suggested to mediate the genomic actions of melatonin on the expression of antioxidant enzymes. However, no direct evidences exist. In the present study we explored the role of photoperiod (natural and artificial) in regulation of RORα and its association with the photoperiod induced antioxidant defense system in the lymphoid organs (spleen and thymus) of seasonally breeding, tropical squirrels, Funambulus pennanti. The photoperiod mediated regulation of antioxidant status was checked along with the RORα expression and circulatory melatonin level in the squirrels. The enhancement of the antioxidant capacity of serum and lymphoid organ was concomitant with the short photoperiod (10L:14D) induced high levels of plasma melatonin. Further, peripheral melatonin level enhanced the AANAT activity as well as the melatonin synthesis in the lymphoid tissues. RORα expression presented an inverse correlation with the plasma level of melatonin as well as the short day induced antioxidant enzyme activity in the lymphoid organs. The results suggest that for reduction of seasonal oxidative stress melatonin might not be utilizing the nuclear receptor RORα pathway; rather the rise in circulatory melatonin collectively with tissue specific melatonin might be protecting the splenic and thymic lymphocytes from the seasonal oxidative stress. PMID:25541021

  2. Effect of lead nitrate on thyroid function on the Indian palm squirrel, Funambulus pennanti (Wroughton)

    SciTech Connect

    Shrivastava, V.K.; Katti, S.R.; Sathyanesan, A.G.

    1987-06-01

    Some of the known toxic effects of lead in mammals including man are, impaired heme synthesis, anemia, nepatopathy, nephropathy, behavioral disorders and neuropathy. However, very little is known about the effect of lead on endocrine physiology. Some data are available on lead induced impairment of thyroid function in occupationally exposed men and experimental rats. As lead nitrate is largely consumed through water and food, in this study the wild rodents Funambulus pennanti were administered lead through their drinking water and their thyroid structure, radioiodine 131-I percentage uptake and protein bound iodine (PBI) level were assessed.

  3. Problems associated with the control of rodents in tropical Africa

    PubMed Central

    Gratz, N. G.; Arata, A. A.

    1975-01-01

    As elsewhere in the world, rodents are responsible for very considerable economic losses in tropical Africa because of their depredations on both growing crops and stored food products. Unfortunately, few accurate data are available on the extent of these losses but there is evidence that they are considerable. The public health importance of rodents, both as reservoirs and vectors of disease in tropical Africa, is also great; plague, leptospirosis, murine typhus, and Lassa fever are among the diseases associated with rodent hosts. Scientifically based rodent control programmes have been carried out in very few areas of Africa and there is urgent need for studies and demonstrations on rodent control in both urban and rural areas. The problems likely to be encountered are reviewed and methods of control proposed. PMID:1085224

  4. Problems of rodent control in rural tropical areas

    PubMed Central

    Barnes, Allan M.

    1975-01-01

    Rodent control strategies, techniques, and research needs in rural tropical environments are reviewed and discussed with special reference to Mastomys natalensis, the possible reservoir of Lassa fever in West Africa. Public health rodent problems are far more serious and widespread in rural tropical areas than in developed countries. In the latter, only the commensal rodents constitute a major problem, whereas in rural tropical areas, native semidomestic species also serve as disease reservoirs and sources of infection to man. The success of rodent control programmes in developed countries depends in large part on the willingness and ability of people and governments to spend relatively large sums on research and control, on an acquired intolerance of people to rats and disease, and on a substantial economic base. These prerequisites are not usually to be found in rural tropical areas. Consequently, the rodent control techniques and programme organizations of developed countries are not directly applicable to such areas, even though the principles are the same. For this reason, it is suggested that a well-funded, integrated research and control programme should be undertaken in a known Lassa fever area, stressing public education, personnel training, and environmental management as well as rodenticidal approaches. PMID:1085222

  5. Ancient DNA and the tropics: a rodent's tale

    PubMed Central

    Gutirrez-Garca, Tania A.; Vzquez-Domnguez, Ella; Arroyo-Cabrales, Joaqun; Kuch, Melanie; Enk, Jacob; King, Christine; Poinar, Hendrik N.

    2014-01-01

    Most genetic studies of Holocene fauna have been performed with ancient samples from dry and cold regions, in which preservation of fossils is facilitated and molecular damage is reduced. Ancient DNA work from tropical regions has been precluded owing to factors that limit DNA preservation (e.g. temperature, hydrolytic damage). We analysed ancient DNA from rodent jawbones identified as Ototylomys phyllotis, found in Holocene and Late Pleistocene stratigraphic layers from Loltn, a humid tropical cave located in the Yucatan peninsula. We extracted DNA and amplified six short overlapping fragments of the cytochrome b gene, totalling 666 bp, which represents an unprecedented success considering tropical ancient DNA samples. We performed genetic, phylogenetic and divergence time analyses, combining sequences from ancient and modern O. phyllotis, in order to assess the ancestry of the Loltn samples. Results show that all ancient samples fall into a unique clade that diverged prior to the divergence of the modern O. phyllotis, supporting it as a distinct Pleistocene form of the Ototylomys genus. Hence, this rodent's tale suggests that the sister group to modern O. phyllotis arose during the MiocenePliocene, diversified during the Pleistocene and went extinct in the Holocene. PMID:24899682

  6. Ancient DNA and the tropics: a rodent's tale.

    PubMed

    Gutirrez-Garca, Tania A; Vzquez-Domnguez, Ella; Arroyo-Cabrales, Joaqun; Kuch, Melanie; Enk, Jacob; King, Christine; Poinar, Hendrik N

    2014-06-01

    Most genetic studies of Holocene fauna have been performed with ancient samples from dry and cold regions, in which preservation of fossils is facilitated and molecular damage is reduced. Ancient DNA work from tropical regions has been precluded owing to factors that limit DNA preservation (e.g. temperature, hydrolytic damage). We analysed ancient DNA from rodent jawbones identified as Ototylomys phyllotis, found in Holocene and Late Pleistocene stratigraphic layers from Loltn, a humid tropical cave located in the Yucatan peninsula. We extracted DNA and amplified six short overlapping fragments of the cytochrome b gene, totalling 666 bp, which represents an unprecedented success considering tropical ancient DNA samples. We performed genetic, phylogenetic and divergence time analyses, combining sequences from ancient and modern O. phyllotis, in order to assess the ancestry of the Loltn samples. Results show that all ancient samples fall into a unique clade that diverged prior to the divergence of the modern O. phyllotis, supporting it as a distinct Pleistocene form of the Ototylomys genus. Hence, this rodent's tale suggests that the sister group to modern O. phyllotis arose during the Miocene-Pliocene, diversified during the Pleistocene and went extinct in the Holocene. PMID:24899682

  7. Museum specimen data predict crop damage by tropical rodents

    PubMed Central

    Snchez-Cordero, Vctor; Martnez-Meyer, Enrique

    2000-01-01

    Museum collections constitute a massive store of information on biological diversity. We used museum specimen data to generate ecological niche models that provide predictions of geographic distributions of native rodent pest species and agricultural census data that summarize the geographic distribution of nine crops in the state of Veracruz, Mexico, as well as crop losses between planting and harvest. Herein, we show that crop damage is related significantly to the predicted presence of rodent species for seven of nine crops. Museum collections may thus provide important baseline information for designing land-use and agricultural pest-management programs. PMID:10860973

  8. Lack of immunological responsiveness to photoperiod in a tropical rodent, Peromyscus aztecus hylocetes.

    PubMed

    Demas, G E; Nelson, R J

    2003-03-01

    Non-tropical rodents undergo seasonal changes in immune function and disease. It has been hypothesized that seasonal fluctuations in immunity of non-tropical rodents are due to suppressed immune function during harsh winter conditions. A logical extension of this hypothesis is that seasonal changes in immunity should be reduced or absent in tropical rodents that do not experience marked seasonal fluctuations in environmental conditions; however this hypothesis remains to be tested. The present study tested the effects of photoperiod on humoral and cell-mediated immune function of male Aztec mice ( Peromyscus aztecus hylocetes). P. a. hylocetes were housed in long (L:D 16:8) or short days (L:D 8:16) for 10 weeks. Animals were then immunized with the antigen keyhole limpet hemocyanin (KLH). Serum anti-KLH immunoglobulin G (IgG) concentrations and splenocyte proliferation in response to the T-cell mitogen Concanavalin A were assessed. Short-day P. a. hylocetes did not display differences in reproductive or immune measures compared with long-day mice. Collectively, these results suggest that P. a. hylocetes are reproductively and immunologically non-responsive to photoperiod. This lack of immunological responsiveness is likely due to the relative seasonal stability of their environment compared with temperate zone species. PMID:12624655

  9. Post-dispersal seed removal by ground-feeding rodents in tropical peatlands, Central Kalimantan, Indonesia.

    PubMed

    Blackham, Grace V; Corlett, Richard T

    2015-01-01

    Forested tropical peatlands in Southeast Asia are being rapidly converted to agriculture or degraded into non-forest vegetation. Although large areas have been abandoned, there is little evidence for subsequent forest recovery. As part of a study of forest degradation and recovery, we used seed removal experiments and rodent surveys to investigate the potential role of post-dispersal seed predation in limiting the regeneration of woody plants. Two 14-day seed removal trials were done in deforested and forested peatland habitat in Central Kalimantan, Indonesia. Seeds of Nephelium lappaceum, Syzygium muelleri, Artocarpus heterophyllus (all animal-dispersed) and Combretocarpus rotundatus (wind-dispersed) were tested. Significantly more seeds (82.8%) were removed in forest than non-forest (38.1%) and Combretocarpus had the lowest removal in both habitats. Most handled seeds were eaten in situ and little caching was observed. Six species of rodents were captured in forest and five in non-forest. The most trapped taxa were three Maxomys spp. in forest (85.5% of individuals) and Rattus tiomanicus in non-forest (74.8%). Camera traps confirmed that rodents were responsible for seed removal. Seed predation in deforested areas, which have a much lower seed rain than forest, may contribute to the low density and diversity of regenerating forest. PMID:26369444

  10. Post-dispersal seed removal by ground-feeding rodents in tropical peatlands, Central Kalimantan, Indonesia

    PubMed Central

    Blackham, Grace V.; Corlett, Richard T.

    2015-01-01

    Forested tropical peatlands in Southeast Asia are being rapidly converted to agriculture or degraded into non-forest vegetation. Although large areas have been abandoned, there is little evidence for subsequent forest recovery. As part of a study of forest degradation and recovery, we used seed removal experiments and rodent surveys to investigate the potential role of post-dispersal seed predation in limiting the regeneration of woody plants. Two 14-day seed removal trials were done in deforested and forested peatland habitat in Central Kalimantan, Indonesia. Seeds of Nephelium lappaceum, Syzygium muelleri, Artocarpus heterophyllus (all animal-dispersed) and Combretocarpus rotundatus (wind-dispersed) were tested. Significantly more seeds (82.8%) were removed in forest than non-forest (38.1%) and Combretocarpus had the lowest removal in both habitats. Most handled seeds were eaten in situ and little caching was observed. Six species of rodents were captured in forest and five in non-forest. The most trapped taxa were three Maxomys spp. in forest (85.5% of individuals) and Rattus tiomanicus in non-forest (74.8%). Camera traps confirmed that rodents were responsible for seed removal. Seed predation in deforested areas, which have a much lower seed rain than forest, may contribute to the low density and diversity of regenerating forest. PMID:26369444

  11. Effect of cadmium chloride on thyroid activity of the female Indian palm squirrel, Funambulus pennanti (Wroughton)

    SciTech Connect

    Shrivastava, V.K.; Sathyanesan, A.G.

    1988-02-01

    In humans, exposure to Cadmium (Cd) occurs primarily through inhalation and ingestion. Acute Cd inhalation results in pulmonary edema and respiratory tract irritation; while chronic inhalation causes fibrotic and emphysematous changes in lung tissue as well as damage of renal proximal tubules. Several workers have reviewed the toxic effects of Cd on mammals, including man. In laboratory animals Cd produced kidney damage, testicular necrosis and atrophy, brain hemorrhage, hypertension, liver damage and reduced growth. It also induced changes in the adrenal and thyroid gland in the rat. In this study, squirrels, Funambulus pennanti, were administered a single dose of CdCl/sub 2/ intraperitoneally, and their thyroid structure and radioiodine I/sup 131/ uptake were assessed.

  12. Rodent seed predation: effects on seed survival, recruitment, abundance, and dispersion of bird-dispersed tropical trees.

    PubMed

    Velho, Nandini; Isvaran, Kavita; Datta, Aparajita

    2012-08-01

    Tropical tree species vary widely in their pattern of spatial dispersion. We focus on how seed predation may modify seed deposition patterns and affect the abundance and dispersion of adult trees in a tropical forest in India. Using plots across a range of seed densities, we examined whether seed predation levels by terrestrial rodents varied across six large-seeded, bird-dispersed tree species. Since inter-specific variation in density-dependent seed mortality may have downstream effects on recruitment and adult tree stages, we determined recruitment patterns close to and away from parent trees, along with adult tree abundance and dispersion patterns. Four species (Canarium resiniferum, Dysoxylum binectariferum, Horsfieldia kingii, and Prunus ceylanica) showed high predation levels (78.5-98.7%) and increased mortality with increasing seed density, while two species, Chisocheton cumingianus and Polyalthia simiarum, showed significantly lower seed predation levels and weak density-dependent mortality. The latter two species also had the highest recruitment near parent trees, with most abundant and aggregated adults. The four species that had high seed mortality had low recruitment under parent trees, were rare, and had more spaced adult tree dispersion. Biotic dispersal may be vital for species that suffer density-dependent mortality factors under parent trees. In tropical forests where large vertebrate seed dispersers but not seed predators are hunted, differences in seed vulnerability to rodent seed predation and density-dependent mortality can affect forest structure and composition. PMID:22327614

  13. Seed traits and taxonomic relationships determine the occurrence of mutualisms versus seed predation in a tropical forest rodent and seed dispersal system.

    PubMed

    Wang, Zhenyu; Cao, Lin; Zhang, Zhibin

    2014-06-01

    Although many studies have been carried out on plant-animal mutualistic assemblages, the roles of functional traits and taxonomy in determining both whether interactions involve mutualisms or predation and the structure of such assemblages are unclear. We used semi-natural enclosures to quantitatively assess the interaction strengths between seeds of 8 sympatric tree species and 4 rodent species in a tropical forest in Xishuangbanna, Yunnan, Southwest China. We found 2 clusters of species in the seed-rodent network represented by 2 genera in the Fagaceae (Castanopsis, Lithocarpus). Compared to seeds of 3 Castanopsis species, seeds with heavy weight, hard coat or caloric content (including 3 Lithocarpus species) were eaten less and more frequently hoarded by rodents. In turn, hoarded seeds showed less predation and more mutualism with rodents. Our results suggest that seed traits significantly affected the hoarding behavior of rodents, and, consequently, the occurrence of mutualisms and predation as well as assemblage structure in the plant-animal seed dispersal system. Taxonomically-related species with similar seed traits as functional groups belong to the same substructures in the assemblage. Our results indicate that both seed traits and taxonomic relationships may simplify thinking about seed dispersal systems by helping to elucidate whether interactions are likely to be dominated by predation or mutualism. PMID:24382317

  14. Indirect interactions among tropical tree species through shared rodent seed predators: a novel mechanism of tree species coexistence.

    PubMed

    Garzon-Lopez, Carol X; Ballesteros-Mejia, Liliana; Ordoez, Alejandro; Bohlman, Stephanie A; Olff, Han; Jansen, Patrick A

    2015-08-01

    The coexistence of numerous tree species in tropical forests is commonly explained by negative dependence of recruitment on the conspecific seed and tree density due to specialist natural enemies that attack seeds and seedlings ('Janzen-Connell' effects). Less known is whether guilds of shared seed predators can induce a negative dependence of recruitment on the density of different species of the same plant functional group. We studied 54 plots in tropical forest on Barro Colorado Island, Panama, with contrasting mature tree densities of three coexisting large seeded tree species with shared seed predators. Levels of seed predation were far better explained by incorporating seed densities of all three focal species than by conspecific seed density alone. Both positive and negative density dependencies were observed for different species combinations. Thus, indirect interactions via shared seed predators can either promote or reduce the coexistence of different plant functional groups in tropical forest. PMID:25939379

  15. Rodent Control

    ERIC Educational Resources Information Center

    Indian Journal of Adult Education, 1975

    1975-01-01

    Strategies for rodent control in crop fields, threshing yards, and rural residential areas are presented together with an operational plan for implementing a program for rodent control at the national level. Training personnel in rodent control procedures and procedures for educating the public in the necessity for control are covered. (EC)

  16. Rodent repellency

    USGS Publications Warehouse

    DeWitt, J.B.; Welch, J.F.; Bellack, E.

    1950-01-01

    In the course of studies involving more than 2,500 chemical repellents, it has been found that certain groups of- compounds containing nitrogen or sulfur are repellent to rats under the , test conditions and it appears probable that some of these compounds might be used for the protection of packaged goods against rodent attacks. Additional tests to determine optimum methods of application will be necessary before final evaluation of these compounds will be possible and extensive field trials will be required to establish the degree of protection which may be afforded by the use of these materials. Pending such final evaluation, it may be assumed that the results,to date offer a means of selecting the most promising types of'materials for further trial....On the basis of the test data, it appears that some amine derivative, such as a salt of some organic, acid, or a complex with trinitrobenzene or with a metallic salt of a dialkyl dithiocarbamic acid might offer promise of protection of packaging materials against rodent attacks....Protection might be obtained through the use of certain 'physical deterrents' such as plastics, waxes or drying oils.

  17. Rodents And Other Gnawers.

    ERIC Educational Resources Information Center

    Naturescope, 1986

    1986-01-01

    Presents information about rodents and lagomorphs, including definitions and the characteristics of these animals. Contains teaching activities such as "Habitats for Hoppers,""Cartoon Gnawers," and "The Great Rodent Expedition." Reproducible handouts for two of the activities are provided. (TW)

  18. Rodent Research-1 Validation of Rodent Hardware

    NASA Technical Reports Server (NTRS)

    Globus, Ruth; Beegle, Janet

    2013-01-01

    To achieve novel science objectives, validation of a rodent habitat on ISS will enable - In-flight analyses during long duration spaceflight- Use of genetically altered animals- Application of modern analytical techniques (e.g. genomics, proteomics, and metabolomics)

  19. Zoonoses of rabbits and rodents.

    PubMed

    Hill, William Allen; Brown, Julie Paige

    2011-09-01

    Millions of households in the US own rabbits or rodents, including hamsters, guinea pigs, and gerbils. Activities such as hunting and camping also involve human interactions with wild rabbits and rodents. In many environments, feral rabbits and rodents live in close proximity to humans, domesticated animals, and other wildlife. Education of rodent and rabbit owners and individuals with occupational or recreational exposures to these species is paramount to reduce the prevalence of zoonoses associated with rabbit and rodent exposure. PMID:21872786

  20. The largest fossil rodent

    PubMed Central

    Rinderknecht, Andrs; Blanco, R. Ernesto

    2008-01-01

    The discovery of an exceptionally well-preserved skull permits the description of the new South American fossil species of the rodent, Josephoartigasia monesi sp. nov. (family: Dinomyidae; Rodentia: Hystricognathi: Caviomorpha). This species with estimated body mass of nearly 1000?kg is the largest yet recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains. The fossil derives from San Jos Formation, Uruguay, usually assigned to the PliocenePleistocene (42?Myr ago), and the proposed palaeoenvironment where this rodent lived was characterized as an estuarine or deltaic system with forest communities. PMID:18198140

  1. TECHNIQUES IN ASEPTIC RODENT SURGERY

    PubMed Central

    Hoogstraten-Miller, Shelley L.; Brown, Patricia A.

    2008-01-01

    Performing aseptic survival surgery in rodents can be challenging. This unit describes some basic principles to assist clinicians, researchers, and technicians in becoming proficient in performing aseptic rodent surgery. PMID:18729061

  2. Rodent models of osteoporosis

    PubMed Central

    Sophocleous, Antonia; Idris, Aymen I

    2014-01-01

    The aim of this protocol is to provide a detailed description of male and female rodent models of osteoporosis. In addition to indications on the methods of performing the surgical procedures, the choice of reliable and safe anaesthetics is also described. Post-operative care, including analgesia administration for pain management, is also discussed. Ovariectomy in rodents is a procedure where ovaries are surgically excised. Hormonal changes resulting from ovary removal lead to an oestrogen-deprived state, which enhances bone remodelling, causes bone loss and increases bone fracture risk. Therefore, ovariectomy has been considered as the most common preclinical model for understanding the pathophysiology of menopause-associated events and for developing new treatment strategies for tackling post-menopausal osteoporosis. This protocol also provides a detailed description of orchidectomy, a model for androgen-deficient osteoporosis in rodents. Endocrine changes following testes removal lead to hypogonadism, which results in accelerated bone loss, increasing osteoporosis risk. Orchidectomised rodent models have been proposed to mimic male osteoporosis and therefore remain a valuable tool for understanding androgen deficiency in aged men. Although it would have been particularly difficult to assemble an internationally acceptable description of surgical procedures, here we have attempted to provide a comprehensive guide for best practice in performing ovariectomy and orchidectomy in laboratory rodents. Research scientists are reminded that they should follow their own institution's interpretation of such guidelines. Ultimately, however, all animal procedures must be overseen by the local Animal Welfare and Ethical Review Body and conducted under licences approved by a regulatory ethics committee. PMID:25852854

  3. Microdialysis in Rodents

    PubMed Central

    Zapata, Agustin; Chefer, Vladimir I.; Shippenberg, Toni S.

    2010-01-01

    Microdialysis is an in vivo sampling technique that permits the quantification of various substances (e.g., neurotransmitters, peptides, electrolytes) in blood and tissue. It is also used to infuse substances into the brain and spinal cord. This unit describes methods for the construction and stereotaxic implantation of microdialysis probes into discrete brain regions of the rat and mouse. Procedures for the conduct of conventional and quantitative microdialysis experiments in the awake and anesthetized rodent are also provided. PMID:19340813

  4. Geomagnetic field detection in rodents

    SciTech Connect

    Olcese, J.; Reuss, S.; Semm, P.

    1988-01-01

    In addition to behavioral evidence for the detection of earth-strength magnetic fields (MF) by rodents, recent investigations have revealed that electrophysiological and biochemical responses to MF occur in the pineal organ and retina of rodents. In addition, ferrimagnetic deposits have been identified in the ethmoidal regions of the rodent skull. These findings point to a new sensory phenomenon, which interfaces with many fields of biology, including neuroscience, psychophysics, behavioral ecology, chronobiology and sensory physiology.

  5. Thieving rodents as substitute dispersers of megafaunal seeds

    PubMed Central

    Jansen, Patrick A.; Hirsch, Ben T.; Emsens, Willem-Jan; Zamora-Gutierrez, Veronica; Wikelski, Martin; Kays, Roland

    2012-01-01

    The Neotropics have many plant species that seem to be adapted for seed dispersal by megafauna that went extinct in the late Pleistocene. Given the crucial importance of seed dispersal for plant persistence, it remains a mystery how these plants have survived more than 10,000 y without their mutualist dispersers. Here we present support for the hypothesis that secondary seed dispersal by scatter-hoarding rodents has facilitated the persistence of these large-seeded species. We used miniature radio transmitters to track the dispersal of reputedly megafaunal seeds by Central American agoutis, which scatter-hoard seeds in shallow caches in the soil throughout the forest. We found that seeds were initially cached at mostly short distances and then quickly dug up again. However, rather than eating the recovered seeds, agoutis continued to move and recache the seeds, up to 36 times. Agoutis dispersed an estimated 35% of seeds for >100 m. An estimated 14% of the cached seeds survived to the next year, when a new fruit crop became available to the rodents. Serial video-monitoring of cached seeds revealed that the stepwise dispersal was caused by agoutis repeatedly stealing and recaching each others buried seeds. Although previous studies suggest that rodents are poor dispersers, we demonstrate that communities of rodents can in fact provide highly effective long-distance seed dispersal. Our findings suggest that thieving scatter-hoarding rodents could substitute for extinct megafaunal seed dispersers of tropical large-seeded trees. PMID:22802644

  6. Toxoplasmosis seroprevalence in urban rodents: a survey in Niamey, Niger

    PubMed Central

    Mercier, Aurélien; Garba, Madougou; Bonnabau, Henri; Kane, Mamadou; Rossi, Jean-Pierre; Dardé, Marie-Laure; Dobigny, Gauthier

    2013-01-01

    A serological survey of Toxoplasma gondii was conducted on 766 domestic and peridomestic rodents from 46 trapping sites throughout the city of Niamey, Niger. A low seroprevalence was found over the whole town with only 1.96% of the rodents found seropositive. However, differences between species were important, ranging from less than 2% in truly commensal Mastomys natalensis, Rattus rattus and Mus musculus, while garden-associated Arvicanthis niloticus displayed 9.1% of seropositive individuals. This is in line with previous studies on tropical rodents - that we reviewed here - which altogether show that Toxoplasma seroprevalence in rodent is highly variable, depending on many factors such as locality and/or species. Moreover, although we were not able to decipher statistically between habitat or species effect, such a contrast between Nile grass rats and the other rodent species points towards a potentially important role of environmental toxoplasmic infection. This would deserve to be further scrutinised since intra-city irrigated cultures are extending in Niamey, thus potentially increasing Toxoplasma circulation in this yet semi-arid region. As far as we are aware of, our study is one of the rare surveys of its kind performed in Sub-Saharan Africa and the first one ever conducted in the Sahel. PMID:23828008

  7. Rodent carcinogens: Setting priorities

    SciTech Connect

    Gold, L.S.; Slone, T.H.; Stern, B.R.; Manley, N.B.; Ames, B.N. )

    1992-10-09

    The human diet contains an enormous background of natural chemicals, such as plant pesticides and the products of cooking, that have not been a focus of carcinogenicity testing. A broadened perspective that includes these natural chemicals is necessary. A comparison of possible hazards for 80 daily exposures to rodent carcinogens from a variety of sources is presented, using an index (HERP) that relates human exposure to carcinogenic potency in rodents. A similar ordering would be expected with the use of standard risk assessment methodology for the same human exposure values. Results indicate that, when viewed against the large background of naturally occurring carcinogens in typical portions of common foods, the residues of synthetic pesticides or environmental pollutants rank low. A similar result is obtained in a separate comparison of 32 average daily exposures to natural pesticides and synthetic pesticides residues in the diet. Although the findings do not indicate that these natural dietary carcinogens are important in human cancer, they cast doubt on the relative importance for human cancer of low-dose exposures to synthetic chemicals.

  8. Aquaporins in desert rodent physiology.

    PubMed

    Pannabecker, Thomas L

    2015-08-01

    Desert rodents face a sizeable challenge in maintaining salt and water homeostasis due to their life in an arid environment. A number of their organ systems exhibit functional characteristics that limit water loss above that which occurs in non-desert species under similar conditions. These systems include renal, pulmonary, gastrointestinal, nasal, and skin epithelia. The desert rodent kidney preserves body water by producing a highly concentrated urine that reaches a maximum osmolality nearly three times that of the common laboratory rat. The precise mechanism by which urine is concentrated in any mammal is unknown. Insights into the process may be more apparent in species that produce highly concentrated urine. Aquaporin water channels play a fundamental role in water transport in several desert rodent organ systems. The role of aquaporins in facilitating highly effective water preservation in desert rodents is only beginning to be explored. The organ systems of desert rodents and their associated AQPs are described. PMID:26338874

  9. Tropical Rainforests.

    ERIC Educational Resources Information Center

    Nigh, Ronald B.; Nations, James D.

    1980-01-01

    Presented is a summary of scientific knowledge about the rainforest environment, a tropical ecosystem in danger of extermination. Topics include the current state of tropical rainforests, the causes of rainforest destruction, and alternatives of rainforest destruction. (BT)

  10. Correlates of Recent Declines of Rodents in Northern and Southern Australia: Habitat Structure Is Critical

    PubMed Central

    Lawes, Michael J.; Fisher, Diana O.; Johnson, Chris N.; Blomberg, Simon P.; Frank, Anke S. K.; Fritz, Susanne A.; McCallum, Hamish; VanDerWal, Jeremy; Abbott, Brett N.; Legge, Sarah; Letnic, Mike; Thomas, Colette R.; Thurgate, Nikki; Fisher, Alaric; Gordon, Iain J.; Kutt, Alex

    2015-01-01

    Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in the south. We examine potential regional effects (northern versus southern Australia) on biological and ecological correlates of range decline in Australian rodents. We demonstrate that rodent declines have been greater in the south than in the tropical north, are strongly influenced by phylogeny, and are consistently greater for species inhabiting relatively open or sparsely vegetated habitat. Unlike in marsupials, where some species have much larger body size than rodents, body mass was not an important predictor of decline in rodents. All Australian rodent species are within the prey-size range of cats (throughout the continent) and red foxes (in the south). Contrary to the hypothesis that mammal declines are related directly to ecosystem productivity (annual rainfall), our results are consistent with the hypothesis that disturbances such as fire and grazing, which occur in non-rainforest habitats and remove cover used by rodents for shelter, nesting and foraging, increase predation risk. We agree with calls to introduce conservation management that limits the size and intensity of fires, increases fire patchiness and reduces grazing impacts at ecological scales appropriate for rodents. Controlling feral predators, even creating predator-free reserves in relatively sparsely-vegetated habitats, is urgently required to ensure the survival of rodent species, particularly in northern Australia where declines are not yet as severe as those in the south. PMID:26111037

  11. Correlates of Recent Declines of Rodents in Northern and Southern Australia: Habitat Structure Is Critical.

    PubMed

    Lawes, Michael J; Fisher, Diana O; Johnson, Chris N; Blomberg, Simon P; Frank, Anke S K; Fritz, Susanne A; McCallum, Hamish; VanDerWal, Jeremy; Abbott, Brett N; Legge, Sarah; Letnic, Mike; Thomas, Colette R; Thurgate, Nikki; Fisher, Alaric; Gordon, Iain J; Kutt, Alex

    2015-01-01

    Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in the south. We examine potential regional effects (northern versus southern Australia) on biological and ecological correlates of range decline in Australian rodents. We demonstrate that rodent declines have been greater in the south than in the tropical north, are strongly influenced by phylogeny, and are consistently greater for species inhabiting relatively open or sparsely vegetated habitat. Unlike in marsupials, where some species have much larger body size than rodents, body mass was not an important predictor of decline in rodents. All Australian rodent species are within the prey-size range of cats (throughout the continent) and red foxes (in the south). Contrary to the hypothesis that mammal declines are related directly to ecosystem productivity (annual rainfall), our results are consistent with the hypothesis that disturbances such as fire and grazing, which occur in non-rainforest habitats and remove cover used by rodents for shelter, nesting and foraging, increase predation risk. We agree with calls to introduce conservation management that limits the size and intensity of fires, increases fire patchiness and reduces grazing impacts at ecological scales appropriate for rodents. Controlling feral predators, even creating predator-free reserves in relatively sparsely-vegetated habitats, is urgently required to ensure the survival of rodent species, particularly in northern Australia where declines are not yet as severe as those in the south. PMID:26111037

  12. Rodent Control: Seal Up! Trap Up! Clean Up!

    MedlinePLUS

    ... transmitted by rodents Diseases indirectly transmitted by rodents Cleaning up after rodents Take precautions before and during clean up of rodent-infested areas. Before cleaning, trap the rodents and seal up any entryways ...

  13. Rodent Empathy and Affective Neuroscience

    PubMed Central

    Panksepp, Jules B.; Lahvis, Garet P.

    2011-01-01

    In the past few years, several experimental studies have suggested that empathy occurs in the social lives of rodents. This indicates that rodent behavioral models can be developed in an attempt to elucidate the mechanistic substrates of empathy at levels that have heretofore been unavailable. For example, the finding that mice from certain inbred strains express behavioral and physiological responses to conspecific distress, while others do not, underscores that the genetic underpinnings of empathy are specifiable and that in the future they could be harnessed to develop new therapies for human psychosocial impairments. However, the advent of rodent models of empathy is met at the outset with a number of theoretical and semantic problems that are similar to those previously confronted by studies of empathy in humans. The distinct underlying components of empathy must be differentiated from one another and from lay usage of the term. The primary goal of this paper is to review a set of seminal studies that are directly relevant to developing a concept of empathy in rodents. We first consider some of the psychological phenomena that have been associated with empathy, and within this context, we consider the component processes, or endophenotypes of rodent empathy. We then review a series of recent experimental studies that demonstrate the capability of rodents to detect and respond to the affective state of their social partners. We focus primarily on experiments that examine how rodents share affective experiences of fear, but we also highlight how similar types of experimental paradigms can be utilized to evaluate the possibility that rodents share positive affective experiences. Taken together, these studies were inspired by Jaak Panksepp’s theory that all mammals are capable of felt affective experiences. PMID:21672550

  14. Tropical myelopathies.

    PubMed

    Romn, Gustavo C

    2014-01-01

    A large number of causal agents produce spinal cord lesions in the tropics. Most etiologies found in temperate regions also occur in the tropics including trauma, herniated discs, tumors, epidural abscess, and congenital malformations. However, infectious and nutritional disorders occur with higher prevalence in tropical regions. Among the most common infectious etiologies are tuberculous Pott's disease, brucellosis, and neuroborreliosis. Parasitic diseases such as schistosomiasis, neurocysticercosis, and eosinophilic meningitis are frequent causes of nontraumatic paraplegia. The retrovirus HTLV-1 is a cause of tropical spastic paraparesis. Nutritional causes of paraparesis include deficiencies of vitamin B12 and folate; endemic clusters of konzo and tropical ataxic myeloneuropathy are associated in Africa with malnutrition and excessive consumption of cyanide-containing bitter cassava. Other toxic etiologies of tropical paraplegia include lathyrism and fluorosis. Nutritional forms of myelopathy are associated often with optic and sensory neuropathy, hence the name tropical myeloneuropathies. Acute transverse myelopathy is seen in association with vaccination, infections, and fibrocartilaginous embolism of the nucleus pulposus. Multiple sclerosis and optic myelopathy occur in the tropics but with lesser prevalence than in temperate regions. The advent of modern imaging in the tropics, including computed tomography and magnetic resonance imaging, has allowed better diagnosis and treatment of these conditions that are a frequent cause of death and disability. PMID:24365434

  15. A pseudoseasonal reproductive strategy in a tropical rodent, Peromyscus nudipes.

    PubMed

    Heideman, P D; Bronson, F H

    1992-05-01

    A population of cloud forest mice (Peromyscus nudipes) at latitude 10 degrees N near Monteverde, Costa Rica, was sampled four times by live-trapping twice during the 7-8 month wet season and twice during the 4-5 month dry season in 1989 and 1990. Body weights were lower during the early part of the dry season in males and throughout the dry season in females than at other times. Testes and seminal vesicles were somewhat lighter early in the dry season, but epididymal spermatozoa were abundant in most males throughout the year. Adult females ovulated, mated and became pregnant in the wet and dry seasons, but young were produced only during the wet season. Most embryos failed to implant during the dry season, and the few that did complete implantation were reabsorbed before midpregnancy. Apparently, every year, the females in this population spend several months actively engaged in a behavioural and metabolically costly process that is doomed to be unsuccessful. This reproductive strategy is termed pseudoseasonal, because reproductive success is highly seasonal, but attempts to reproduce are nonseasonal. Implantation failures similar to those seen in the wild were induced in the laboratory using mild restriction of food or water. Field evidence points to food restriction as the more important cause of pregnancy losses in the wild. Exposure to the gradually changing daylengths typical of Costa Rica had no effect on the production of young by adults, and maintenance on light cycles of 8 h light: 16 h dark, 11 h light: 13 h dark, 13 h light: 11 h dark and 16 h light: 8 h dark had no effect on the reproductive development of young animals of either sex. PMID:1625250

  16. Rodent nutrition: digestive comparisons of 4 common rodent species.

    PubMed

    Grant, Kerrin

    2014-09-01

    This article summarizes the literature regarding digestive strategies and captive diets of common rodent pocket pets. A comparison is made between the 2 suborders in which chinchillas, guinea pigs, hamsters, and gerbils occur, highlighting digestive anatomy and dietary adaptations. Recommended captive diets are provided, as well as common nutritionally related health issues that may be presented to veterinary clinics. PMID:25155666

  17. Tropical rivers

    NASA Astrophysics Data System (ADS)

    Latrubesse, E. M.; Stevaux, J. C.; Sinha, R.

    2005-09-01

    This paper presents an overview of tropical river systems around the world and identifies major knowledge gaps. We focus particularly on the rivers draining the wet and wet-dry tropics with annual rainfall of more than 700 mm/year. The size of the analyzed river basins varies from 10 4 to 6 10 6 km 2. The tropical rivers across the globe drain a variety of geologic-geomorphologic settings: (a) orogenic mountains belts, (b) sedimentary and basaltic plateau/platforms, (c) cratonic areas, (d) lowland plains in sedimentary basins and (e) mixed terrain. All of them show clearly high but variable peak discharges during the rainy season and a period of low flow when rainfall decreases. Some tropical rivers show two flood peaks, a principal and a secondary one, during the year. We computed the intensity of floods and discharge variability in tropical rivers. The relationship between sediment yield and average water discharge for orogenic continental rivers of South America and Asia was also plotted. Insular Asian rivers show lower values of sediment yield related to mean annual discharge than continental orogenic rivers of Asia and South America. Rivers draining platforms or cratonic areas in savanna and wet tropical climates are characterized by low sediment yields. Tropical rivers exhibit a large variety of channel form. In most cases, and particularly in large basins, rivers exhibit a transition from one form to another so that traditional definitions of straight, meandering and braided may be difficult to apply. In general, it is more useful to apply the terminology of single and multi-channel systems or complex anabranching systems at least for selected regional segments. Present-day knowledge of tropical systems and its potential application to improve interpretation of older alluvial sequences and facies models are briefly discussed. Human impact and river management issues including land use changes, mining, dams, interbasin water transference as well as flood hazards are some of the daunting problems in tropical river basins today.

  18. Allometric disparity in rodent evolution

    PubMed Central

    Wilson, Laura A B

    2013-01-01

    In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents. PMID:23610638

  19. 21 CFR 1250.96 - Rodent control.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Rodent control. 1250.96 Section 1250.96 Food and... SANITATION Sanitation Facilities and Conditions on Vessels 1250.96 Rodent control. Vessels shall be... of rodent control....

  20. 21 CFR 1250.96 - Rodent control.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Rodent control. 1250.96 Section 1250.96 Food and... SANITATION Sanitation Facilities and Conditions on Vessels 1250.96 Rodent control. Vessels shall be... of rodent control....

  1. 21 CFR 1250.96 - Rodent control.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Rodent control. 1250.96 Section 1250.96 Food and... SANITATION Sanitation Facilities and Conditions on Vessels 1250.96 Rodent control. Vessels shall be maintained free of rodent infestation through the use of traps, poisons, and other generally accepted...

  2. 21 CFR 1250.96 - Rodent control.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Rodent control. 1250.96 Section 1250.96 Food and... SANITATION Sanitation Facilities and Conditions on Vessels 1250.96 Rodent control. Vessels shall be... of rodent control....

  3. 21 CFR 1250.96 - Rodent control.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rodent control. 1250.96 Section 1250.96 Food and... SANITATION Sanitation Facilities and Conditions on Vessels 1250.96 Rodent control. Vessels shall be... of rodent control....

  4. Rodent models of cerebral ischemia

    SciTech Connect

    Ginsberg, M.D.; Busto, R. )

    1989-12-01

    The use of physiologically regulated, reproducible animal models is crucial to the study of ischemic brain injury--both the mechanisms governing its occurrence and potential therapeutic strategies. Several laboratory rodent species (notably rats and gerbils), which are readily available at relatively low cost, are highly suitable for the investigation of cerebral ischemia and have been widely employed for this purpose. We critically examine and summarize several rodent models of transient global ischemia, resulting in selective neuronal injury within vulnerable brain regions, and focal ischemia, typically giving rise to localized brain infarction. We explore the utility of individual models and emphasize the necessity for meticulous experimental control of those variables that modulate the severity of ischemic brain injury.169 references.

  5. Rodent consumption in Khon Kaen Province, Thailand.

    PubMed

    Suwannarong, Kanokwan; Chapman, Robert S

    2014-09-01

    Rodents are important reservoirs of rodent-borne infections worldwide, including Southeast Asia and Northeast Thailand (Isaan), where rodent consumption may be a source of rodent-borne diseases. The behavior of consuming rodents is related to a population's traditions, knowledge, cultural, and household contexts, among other factors. This cross-sectional survey was conducted in Khon Kaen Province, Thailand during November-December 2011. It aimed to elicit information about rodent consumption among residents of this province, and to identify factors associated with rodent consumption there. Multiple logistic regression analysis indicated that male gender, large family size, and use of rainwater as the main source of drinking water were positively associated with reported rodent consumption in this province, while having proper knowledge/attitudes towards animal-borne disease was negatively associated. These results provide evidence-base information for further studies, such as participatory ac- tion research, to further explore how people interact with rodents in different contexts. Further research is also needed to characterize risk of zoonotic diseases in relation to rodent consumption. PMID:25417525

  6. Rodent consumption in Khon Kaen Province, Thailand.

    PubMed

    Suwannarong, Kanokwan; Chapman, Robert S

    2014-09-01

    Rodents are important reservoirs of rodent-borne infections worldwide, including Southeast Asia and Northeast Thailand (Isaan), where rodent consumption may be a source of rodent-borne diseases. The behavior of consuming rodents is related to a population's traditions, knowledge, cultural, and household contexts, among other factors. This cross-sectional survey was conducted in Khon Kaen Province, Thailand during November-December 2011. It aimed to elicit information about rodent consumption among residents of this province, and to identify factors associated with rodent consumption there. Multiple logistic regression analysis indicated that male gender, large family size, and use of rainwater as the main source of drinking water were positively associated with reported rodent consumption in this province, while having proper knowledge/attitudes towards animal-borne disease was negatively associated. These results provide evidence-base information for further studies, such as participatory ac- tion research, to further explore how people interact with rodents in different contexts. Further research is also needed to characterize risk of zoonotic diseases in relation to rodent consumption. PMID:25507253

  7. Tracking Seed Fates of Tropical Tree Species: Evidence for Seed Caching in a Tropical Forest in North-East India.

    PubMed

    Sidhu, Swati; Datta, Aparajita

    2015-01-01

    Rodents affect the post-dispersal fate of seeds by acting either as on-site seed predators or as secondary dispersers when they scatter-hoard seeds. The tropical forests of north-east India harbour a high diversity of little-studied terrestrial murid and hystricid rodents. We examined the role played by these rodents in determining the seed fates of tropical evergreen tree species in a forest site in north-east India. We selected ten tree species (3 mammal-dispersed and 7 bird-dispersed) that varied in seed size and followed the fates of 10,777 tagged seeds. We used camera traps to determine the identity of rodent visitors, visitation rates and their seed-handling behavior. Seeds of all tree species were handled by at least one rodent taxon. Overall rates of seed removal (44.5%) were much higher than direct on-site seed predation (9.9%), but seed-handling behavior differed between the terrestrial rodent groups: two species of murid rodents removed and cached seeds, and two species of porcupines were on-site seed predators. In addition, a true cricket, Brachytrupes sp., cached seeds of three species underground. We found 309 caches formed by the rodents and the cricket; most were single-seeded (79%) and seeds were moved up to 19 m. Over 40% of seeds were re-cached from primary cache locations, while about 12% germinated in the primary caches. Seed removal rates varied widely amongst tree species, from 3% in Beilschmiedia assamica to 97% in Actinodaphne obovata. Seed predation was observed in nine species. Chisocheton cumingianus (57%) and Prunus ceylanica (25%) had moderate levels of seed predation while the remaining species had less than 10% seed predation. We hypothesized that seed traits that provide information on resource quantity would influence rodent choice of a seed, while traits that determine resource accessibility would influence whether seeds are removed or eaten. Removal rates significantly decreased (p < 0.001) while predation rates increased (p = 0.06) with seed size. Removal rates were significantly lower for soft seeds (p = 0.002), whereas predation rates were significantly higher on soft seeds (p = 0.01). Our results show that murid rodents play a very important role in affecting the seed fates of tropical trees in the Eastern Himalayas. We also found that the different rodent groups differed in their seed handling behavior and responses to changes in seed characteristics. PMID:26247616

  8. Tracking Seed Fates of Tropical Tree Species: Evidence for Seed Caching in a Tropical Forest in North-East India

    PubMed Central

    Sidhu, Swati; Datta, Aparajita

    2015-01-01

    Rodents affect the post-dispersal fate of seeds by acting either as on-site seed predators or as secondary dispersers when they scatter-hoard seeds. The tropical forests of north-east India harbour a high diversity of little-studied terrestrial murid and hystricid rodents. We examined the role played by these rodents in determining the seed fates of tropical evergreen tree species in a forest site in north-east India. We selected ten tree species (3 mammal-dispersed and 7 bird-dispersed) that varied in seed size and followed the fates of 10,777 tagged seeds. We used camera traps to determine the identity of rodent visitors, visitation rates and their seed-handling behavior. Seeds of all tree species were handled by at least one rodent taxon. Overall rates of seed removal (44.5%) were much higher than direct on-site seed predation (9.9%), but seed-handling behavior differed between the terrestrial rodent groups: two species of murid rodents removed and cached seeds, and two species of porcupines were on-site seed predators. In addition, a true cricket, Brachytrupes sp., cached seeds of three species underground. We found 309 caches formed by the rodents and the cricket; most were single-seeded (79%) and seeds were moved up to 19 m. Over 40% of seeds were re-cached from primary cache locations, while about 12% germinated in the primary caches. Seed removal rates varied widely amongst tree species, from 3% in Beilschmiedia assamica to 97% in Actinodaphne obovata. Seed predation was observed in nine species. Chisocheton cumingianus (57%) and Prunus ceylanica (25%) had moderate levels of seed predation while the remaining species had less than 10% seed predation. We hypothesized that seed traits that provide information on resource quantity would influence rodent choice of a seed, while traits that determine resource accessibility would influence whether seeds are removed or eaten. Removal rates significantly decreased (p < 0.001) while predation rates increased (p = 0.06) with seed size. Removal rates were significantly lower for soft seeds (p = 0.002), whereas predation rates were significantly higher on soft seeds (p = 0.01). Our results show that murid rodents play a very important role in affecting the seed fates of tropical trees in the Eastern Himalayas. We also found that the different rodent groups differed in their seed handling behavior and responses to changes in seed characteristics. PMID:26247616

  9. An epidemiological comparative study on diagnosis of rodent leptospirosis in Mazandaran Province, northern Iran

    PubMed Central

    Esfandiari, Behzad; Pourshafie, Mohammad Reza; Gouya, Mohammad Mehdi; Khaki, Pejvak; Mostafavi, Ehsan; Darvish, Jamshid; Bidhendi, Soheila Moradi; Hanifi, Hamed; Nahrevanian, Hossein

    2015-01-01

    OBJECTIVES: Leptospirosis is a zoonosis caused by leptospires, in which transmission occurs through contact with contaminated biological fluids from infected animals. Rodents can act as a source of infection for humans and animals. The disease has a global distribution, mainly in humid, tropical and sub-tropical regions. The aim of this study was to compare culture assays, the microscopic agglutination test (MAT), polymerase chain reaction (PCR), and nested PCR (n-PCR), for the diagnosis of leptospirosis in rodents in Mazandaran Province, northern Iran. METHODS: One hundred fifty-one rodents were trapped alive at 10 locations, and their urine and kidney samples were collected and used for the isolation of live Leptospira. The infecting serovars were identified and the antibody titres were measured by MAT, using a panel of 20 strains of live Leptospira species as antigens. The presence of leptospiral DNA was evaluated in urine and kidney samples using PCR and n-PCR. RESULTS: No live leptospires were isolated from the kidney and urine samples of the rodents. Different detection rates of leptospirosis were observed with MAT (21.2%), PCR (11.3%), and n-PCR (3.3%). The dominant strain was Leptospira serjoehardjo (34.4%, p=0.28), although other serotypes were also found. The prevalence of positive leptospirosis tests in rodents was 15.9, 2.6, and 2.6% among Rattus norvegicus, R. rattus, and Apodemus sylvaticus, respectively. CONCLUSIONS: Leptospirosis was prevalent in rodents in Mazandaran Province, northern Iran. MAT was able to detect leptospires more frequently than culture or PCR. The kidney was a more suitable site for identifying leptospiral DNA by n-PCR than urine. Culture was not found to be an appropriate technique for clinical diagnosis. PMID:25773440

  10. Tropical Deforestation.

    ERIC Educational Resources Information Center

    Raven, Peter H.

    1988-01-01

    Outlines the deforestation problem and some efforts for solving the problem. Considers the impact of population growth, poverty, and ignorance. Includes a discussion of the current rapid decline in tropical forests, the consequences of destruction, and an outlook for the future. (YP)

  11. Prospects for biological control of rodent populations*

    PubMed Central

    Wodzicki, Kazimierz

    1973-01-01

    Pathogens and predatory animals are the main agents used for the biological control of rodents. The pathogens that have been used are of the genus Salmonella; none is rodent-specific and all can cause severe infection in man and domestic animals. Furthermore, rodents frequently develop immunity to, and become carriers of, these organisms, and there is little to commend their use, except in lightly populated areas where control is infrequently applied. The relationships of five predator species with their rodent prey have been examined. The monitor lizard, mongoose, and ferret were for different reasons found to be unsatisfactory, and there is not yet sufficient evidence to warrant further releases of the Japanese weasel. Domestic and feral cats control rodents well in some situations but only after some other agent has removed a large part of the rodent population. PMID:4587482

  12. Tactile learning in rodents: Neurobiology and neuropharmacology.

    PubMed

    Roohbakhsh, Ali; Shamsizadeh, Ali; Arababadi, Mohammad Kazemi; Ayoobi, Fateme; Fatemi, Iman; Allahtavakoli, Mohammad; Mohammad-Zadeh, Mohammad

    2016-02-15

    Animal models of learning and memory have been the subject of considerable research. Rodents such as mice and rats are nocturnal animals with poor vision, and their survival depends on their sense of touch. Recent reports have shown that whisker somatosensation is the main channel through which rodents collect and process environmental information. This review describes tactile learning in rodents from a neurobiological and neuropharmacological perspective, and how this is involved in memory-related processes. PMID:26800784

  13. Prediction of rodent carcinogenicity for 30 chemicals

    SciTech Connect

    Ashby, J.

    1996-10-01

    Predictions of carcinogenic activity are made for 30 chemicals currently being assessed for rodent carcinogenicity by the U.S. National Toxicology Program. The predictions are based upon the chemical structure, the anticipated or reported mutagenicity, and the reported sub-chronic toxicity of each chemical. It is predicted that 13 chemicals will be noncarcinogenic to rodents, that 7 will be genotoxic carcinogens, and that 10 may show some evidence of presumed nongenotoxic rodent carcinogenesis. 3 refs., 1 fig.

  14. Auditing laboratory rodent biosecurity programs.

    PubMed

    Porter, William P; Horn, Mandy J; Cooper, Dale M; Klein, Hilton J

    2013-10-22

    A rodent biosecurity program that includes periodic evaluation of procedures used in an institution's vivarium can be used to ensure that best practices are in place to prevent a microbial pathogen outbreak. As a result of an ongoing comprehensive biosecurity review within their North American and European production facilities, the authors developed a novel biosecurity auditing process and worksheet that could be useful in other animal care and use operations. The authors encourage other institutions to consider initiating similar audits of their biosecurity programs to protect the health of their laboratory animals. PMID:24150170

  15. Urban resident attitudes toward rodents, rodent control products, and environmental effects

    EPA Science Inventory

    Rodent control in urban areas can result in the inadvertent mortality of non-target species (e.g., bobcats). However, there is little detailed information about rodent control practices of urban residents. Our objective was to evaluate urban rodent control behaviors in two area...

  16. Rodent models for human diseases.

    PubMed

    Vandamme, Thierry F

    2015-07-15

    One of the factors limiting the translation of knowledge from preclinical studies to the clinic has been the limitations of in vivo diseases models. Except in the case of highly controlled and regulated clinical trials, geneticists and scientists do not use humans for their experimental investigations because of the obvious risk to life. Instead, they use various animal, fungal, bacterial, and plant species as model organisms for their studies. Amongst these model organisms, rodent models are the most used due to the easiness for the experiments and the possibility to modify genetically these model animals. Nevertheless, due to the fact that animal models typically do not contract the same genetic diseases as people, so scientists must alter their genomes to induce human disease states and to know what kind of mutation causes the disease. In this brief review, we will discuss the interests of rodent models that have been developed to simulate human pathologies, focusing in models that employ xenografts and genetic modification. Within the framework of genetically engineered mouse (GEM) models, we will review some of the current genetic strategies for modeling diseases. PMID:25823811

  17. The Miocene rodents of Serbia

    NASA Astrophysics Data System (ADS)

    Markovic, Z.

    2009-04-01

    During the Miocene period a group of shallow lakes was created in depressions at the territory of present-day Serbia. This caused the present wide distribution of lacustrine sediments, which occasionally alternate with the alluvial and marsh sediments. The remains of large mammals are relatively common, while the remains of small mammals used to be known only from two localities - Mala Miliva and Sibnica. The method of sediment sieving, used during the last decade, led to discovery of 6 new localities with remains of fossil vertebrates - Sibnica 1, Vračevići, village Lazarevac, Bele Vode, Brajkovac and Tavnik. Most of the fossil material is represented by osteological and odontological remains of small mammals. The best represented group of small mammals at each of the localities was the rodents. According to the odontological material presence was proven for 35 rodent species from 6 families. MN zonation was determined according to structure of associations. The geological age of fossil-bearing sediments was determined by using the method of correlation with the sites in Europe and Turkey.

  18. [Tropical sprue].

    PubMed

    Martnez Salmern, J F; Corral, C; Uariachi, M; Lpez, J; Perales, E; Morales, I

    1994-04-01

    We report the case of a 60 year old female who presented with diarrhoea and malabsorption syndrome, confirmed by the laboratory data and the radiologic examination, which developed after a journey to Egypt. The mainly finding was flattening of the villi in the jejunal biopsy; the syndrome recovered after treatment with antibiotics and folic acid. The case fulfills the diagnostic criteria of tropical sprue although this country is not considered as an endemic area. PMID:8031617

  19. Rodents as agents of ecological change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rodents have the potential to exert a wide array of ecological pressures in any given ecosystem. The negative impacts to plant communities in general, especially cultivated crops, are typically cited as examples of rodent grazing pressure. Considerable research has been conducted on the negative imp...

  20. Tropical Convection's Roles in Tropical Tropopause Cirrus

    NASA Technical Reports Server (NTRS)

    Boehm, Matthew T.; Starr, David OC.; Verlinde, Johannes; Lee, Sukyoung

    2002-01-01

    The results presented here show that tropical convection plays a role in each of the three primary processes involved in the in situ formation of tropopause cirrus. First, tropical convection transports moisture from the surface into the upper troposphere. Second, tropical convection excites Rossby waves that transport zonal momentum toward the ITCZ, thereby generating rising motion near the equator. This rising motion helps transport moisture from where it is detrained from convection to the cold-point tropopause. Finally, tropical convection excites vertically propagating tropical waves (e.g. Kelvin waves) that provide one source of large-scale cooling near the cold-point tropopause, leading to tropopause cirrus formation.

  1. Rodent phylogeny revised: analysis of six nuclear genes from all major rodent clades

    PubMed Central

    Blanga-Kanfi, Shani; Miranda, Hector; Penn, Osnat; Pupko, Tal; DeBry, Ronald W; Huchon, Dorothe

    2009-01-01

    Background Rodentia is the most diverse order of placental mammals, with extant rodent species representing about half of all placental diversity. In spite of many morphological and molecular studies, the family-level relationships among rodents and the location of the rodent root are still debated. Although various datasets have already been analyzed to solve rodent phylogeny at the family level, these are difficult to combine because they involve different taxa and genes. Results We present here the largest protein-coding dataset used to study rodent relationships. It comprises six nuclear genes, 41 rodent species, and eight outgroups. Our phylogenetic reconstructions strongly support the division of Rodentia into three clades: (1) a "squirrel-related clade", (2) a "mouse-related clade", and (3) Ctenohystrica. Almost all evolutionary relationships within these clades are also highly supported. The primary remaining uncertainty is the position of the root. The application of various models and techniques aimed to remove non-phylogenetic signal was unable to solve the basal rodent trifurcation. Conclusion Sequencing and analyzing a large sequence dataset enabled us to resolve most of the evolutionary relationships among Rodentia. Our findings suggest that the uncertainty regarding the position of the rodent root reflects the rapid rodent radiation that occurred in the Paleocene rather than the presence of conflicting phylogenetic and non-phylogenetic signals in the dataset. PMID:19341461

  2. Rodents as potential couriers for bioterrorism agents.

    PubMed

    Lõhmus, Mare; Janse, Ingmar; van de Goot, Frank; van Rotterdam, Bart J

    2013-09-01

    Many pathogens that can cause major public health, economic, and social damage are relatively easily accessible and could be used as biological weapons. Wildlife is a natural reservoir for many potential bioterrorism agents, and, as history has shown, eliminating a pathogen that has dispersed among wild fauna can be extremely challenging. Since a number of wild rodent species live close to humans, rodents constitute a vector for pathogens to circulate among wildlife, domestic animals, and humans. This article reviews the possible consequences of a deliberate spread of rodentborne pathogens. It is relatively easy to infect wild rodents with certain pathogens or to release infected rodents, and the action would be difficult to trace. Rodents can also function as reservoirs for diseases that have been spread during a bioterrorism attack and cause recurring disease outbreaks. As rats and mice are common in both urban and rural settlements, deliberately released rodentborne infections have the capacity to spread very rapidly. The majority of pathogens that are listed as potential agents of bioterrorism by the Centers for Disease Control and Prevention and the National Institute of Allergy and Infectious Diseases exploit rodents as vectors or reservoirs. In addition to zoonotic diseases, deliberately released rodentborne epizootics can have serious economic consequences for society, for example, in the area of international trade restrictions. The ability to rapidly detect introduced diseases and effectively communicate with the public in crisis situations enables a quick response and is essential for successful and cost-effective disease control. PMID:23971813

  3. The Fecal Viral Flora of Wild Rodents

    PubMed Central

    Phan, Tung G.; Kapusinszky, Beatrix; Wang, Chunlin; Rose, Robert K.; Lipton, Howard L.; Delwart, Eric L.

    2011-01-01

    The frequent interactions of rodents with humans make them a common source of zoonotic infections. To obtain an initial unbiased measure of the viral diversity in the enteric tract of wild rodents we sequenced partially purified, randomly amplified viral RNA and DNA in the feces of 105 wild rodents (mouse, vole, and rat) collected in California and Virginia. We identified in decreasing frequency sequences related to the mammalian viruses families Circoviridae, Picobirnaviridae, Picornaviridae, Astroviridae, Parvoviridae, Papillomaviridae, Adenoviridae, and Coronaviridae. Seventeen small circular DNA genomes containing one or two replicase genes distantly related to the Circoviridae representing several potentially new viral families were characterized. In the Picornaviridae family two new candidate genera as well as a close genetic relative of the human pathogen Aichi virus were characterized. Fragments of the first mouse sapelovirus and picobirnaviruses were identified and the first murine astrovirus genome was characterized. A mouse papillomavirus genome and fragments of a novel adenovirus and adenovirus-associated virus were also sequenced. The next largest fraction of the rodent fecal virome was related to insect viruses of the Densoviridae, Iridoviridae, Polydnaviridae, Dicistroviriade, Bromoviridae, and Virgaviridae families followed by plant virus-related sequences in the Nanoviridae, Geminiviridae, Phycodnaviridae, Secoviridae, Partitiviridae, Tymoviridae, Alphaflexiviridae, and Tombusviridae families reflecting the largely insect and plant rodent diet. Phylogenetic analyses of full and partial viral genomes therefore revealed many previously unreported viral species, genera, and families. The close genetic similarities noted between some rodent and human viruses might reflect past zoonoses. This study increases our understanding of the viral diversity in wild rodents and highlights the large number of still uncharacterized viruses in mammals. PMID:21909269

  4. Population cycles in small rodents.

    PubMed

    Krebs, C J; Gaines, M S; Keller, B L; Myers, J H; Tamarin, R H

    1973-01-01

    We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue to reproduce at abnormally high densities until starvation overtakes them. The initial behavioral interactions associated with crowding do not seem sufficient to cause voles to die in situ. What happens to animals during the population decline? Our studies have not answered this question. The animals did not appear to disperse, but it is possible that the method we used to measure dispersal (movement into a vacant habitat) missed a large segment of dispersing voles which did not remain in the vacant area but kept on moving. Perhaps the dispersal during the increase phase of the population cycle is a colonization type of dispersal, and the animals taking part in it are likely to stay in a new habitat, while during the population decline dispersal is a pathological response to high density, and the animals are not attracted to settling even in a vacant habitat. The alternative to this suggestion is that animals are dying in situ during the decline because of physiological or genetically determined behavioral stress. Thus the fencing of a population prevents the change in rates of survival and reproduction, from high rates in the increase phase to low rates in the decline phase, and the fenced populations resemble "mouse plagues." A possible explanation is that the differential dispersal of animals during the phase of increase causes the quality of the voles remaining at peak densities in wild populations to be different from the quality of voles at much higher densities in enclosures. Increased sensitivity to density in Microtus could cause the decline of wild populations at densities lower than those reached by fenced populations in which selection through dispersal has been prevented. Fencing might also alter the social interactions among Microtus in other ways that are not understood. The analysis of colonizing species by MacArthur and Wilson (27) can be applied to our studies of dispersal in populations of Microtus. Groups of organisms with good dispersal and colonizing ability are called r strategists because they have high reproductive potential and are able to exploit a new environment rapidly. Dispersing voles seem to be r strategists. Young females in breeding condition were over-represented in dispersing female Microtus (17). The Tf(C)/Tf(E) females, which were more common among dispersers during the phase of population increase (Fig. 6), also have a slight reproductive advantage over the other Tf genotypes (19). Thus in Microtus populations the animals with the highest reproductive potential, the r strategists, are dispersing. The segment of the population which remains behind after the selection-via-dispersal are those individuals which are less influenced by increasing population densities. These are the individuals which maximize use of the habitat, the K strategists in MacArthur and Wilson's terminology, or voles selected for spacing behavior. Thus we can describe population cycles in Microtus in the same theoretical framework as colonizing species on islands. Our work on Microtus is consistent with the hypothesis of genetic and behavioral effects proposed by Chitty (6) (Fig. 7) in that it shows both behavioral differences in males during the phases of population fluctuation and periods of strong genetic selection. The greatest gaps in our knowledge are in the area of genetic-behavioral interactions which are most difficult to measure. We have no information on the heritability of aggressive behavior in voles. The pathways by which behavioral events are translated into physiological changes which affect reproduction and growth have been carefully analyzed by Christian and his associates (28) for rodents in laboratory situations, but the application of these findings to the complex field events described above remains to be done. Several experiments are suggested by our work. First, other populations of other rodent species should increase to abnormal densities if enclosed in a large fenced area (29). We need to find situations in which this prediction is not fulfilled. Island populations may be an important source of material for such an experiment (30). Second, if one-way exit doors were provided from a fenced area, normal population regulation through dispersal should occur. This experiment would provide another method by which dispersers could be identified. Third, if dispersal were prevented after a population reached peak densities, a normal decline phase should occur. This prediction is based on the assumption that dispersal during the increase phase is sufficient to ensure the decline phase 1 or 2 years later. All these experiments are concerned with the dispersal factor, and our work on Microtus can be summarized by the admonition: study dispersal. PMID:4734149

  5. Rodent-associated Bartonella in Saskatchewan, Canada.

    PubMed

    Jardine, Claire; Appleyard, Greg; Kosoy, Michael Y; McColl, Dorothy; Chirino-Trejo, Manuel; Wobeser, Gary; Leighton, Frederick A

    2005-01-01

    Six species of wild rodents were sampled at 10 sites in 2002 and 2003 to determine the prevalence of Bartonella infections in rodent communities near Saskatoon, Saskatchewan, Canada. Isolates were characterized genotypically and compared with isolates found at other locations. Of 104 wild rodents examined, 57% were infected with Bartonella and prevalence within species varied from 49% for Richardson's ground squirrels (Spermophilus richardsonii) to 90% for Franklin's ground squirrels (S. franklinii). Infected rodents were found at all sites. Sequencing of a 379-bp portion of the citrate synthase gene was performed on 54 isolates and revealed 13 distinct genotypes, eight of which had not been described previously. The most common genotype detected in red-backed voles (Clethrionomys gapperi) was 99.1% similar to B. grahamii, a known human pathogen. Two of 10 Franklin's ground squirrels were concurrently infected with multiple Bartonella genotypes. All genotypes, with the exception of one detected in both Franklin's and thirteen-lined ground squirrels (S. tridecemlineatus), were found in only one host, and all genotypes from each species, with the exception of genotypes detected in red-backed voles, clustered together within the same relatedness group, suggesting that at least some Bartonella genotypes are specific to some rodent hosts. PMID:16417436

  6. Enucleation for Treating Rodent Ocular Disease

    PubMed Central

    Wilding, Laura A; Uchihashi, Mayu; Bergin, Ingrid L; Nowland, Megan H

    2015-01-01

    Our standard of care for rodent corneal lesions previously included treatment of the primary lesion, application of topical NSAIDs, and systemic NSAIDs in severe cases. When intensive medical management was unsuccessful, animals were euthanized, leading to premature loss of valuable genetically modified animals and those on long-term studies. We investigated enucleation surgery as a treatment for 15 cases of rodent corneal disease that did not respond to medical management. Enucleation was performed under isoflurane anesthesia and involved removal of the globe, extensive hemostasis, and packing the orbital space with absorbable gelatin sponge. The lid margins were closed by tarsorrhaphy and tissue glue. Analgesia was provided by using buprenorphine preoperatively and carprofen chew tabs postoperatively. To date, we have a 100% success rate with this procedure (n = 20; 15 clinically affected rodents [2 rats, 13 mice], 5 healthy controls), which included a 60-d follow-up period. The single complication involved dehiscence of the tarsorrhaphy site and was repaired by trimming the lid margins to provide fresh tissue for closure. Histologic examination at both 1 and 3 mo after surgery revealed no evidence of infection of the enucleation site. Enucleation in rodents is a straightforward procedure that represents a refinement to our current standard of care for rodents, does not cause significant inflammation of remaining periocular structures, and has reduced the number of animals euthanized prior to study endpoint because of severe ocular lesions. PMID:26045460

  7. Genetic Rodent Models of Amyotrophic Lateral Sclerosis

    PubMed Central

    Van Den Bosch, L.

    2011-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the selective death of motor neurons in the motor cortex, brainstem, and spinal cord. A large number of rodent models are available that show motor neuron death and a progressive motor phenotype that is more or less reminiscent of what occurs in patients. These rodent models contain genes with spontaneous or induced mutations or (over) express different (mutant) genes. Some of these models have been of great value to delineate potential pathogenic mechanisms that cause and/or modulate selective motor neuron degeneration. In addition, these genetic rodent models play a crucial role in testing and selecting potential therapeutics that can be used to treat ALS and/or other motor neuron disorders. In this paper, we give a systematic overview of the most important genetic rodent models that show motor neuron degeneration and/or develop a motor phenotype. In addition, we discuss the value and limitations of the different models and conclude that it remains a challenge to find more and better rodent models based on mutations in new genes causing ALS. PMID:21274268

  8. Patterns of Species Richness and Turnover for the South American Rodent Fauna

    PubMed Central

    Maestri, Renan; Patterson, Bruce D.

    2016-01-01

    Understanding the spatial distribution of species sheds light on the group’s biogeographical history, offers clues to the drivers of diversity, and helps to guide conservation strategies. Here, we compile geographic range information for South America’s diverse rodents, whose 14 families comprise ~50% of the continent’s mammalian species. The South American rodent fauna is dominated by independent and temporally staggered radiations of caviomorph and sigmodontine groups. We mapped species richness and turnover of all rodents and the principal clades to identify the main predictors of diversity patterns. Species richness was highest in the Andes, with a secondary hotspot in Atlantic Forest and some regions of considerable richness in Amazonia. Differences in richness were evident between the caviomorphs and sigmodontines, the former showing the greatest richness in tropical forests whereas the latter show—and largely determine—the all-rodent pattern. Elevation was the main predictor of sigmodontine richness, whereas temperature was the principal variable correlated with richness of caviomorphs. Across clades, species turnover was highest along the Andes and was best explained by elevational relief. In South America, the effects of the familiar latitudinal gradient in species richness are mixed with a strong longitudinal effect, triggered by the importance of elevation and the position of the Andes. Both latitudinal and elevational effects help explain the complicated distribution of rodent diversity across the continent. The continent’s restricted-range species—those seemingly most vulnerable to localized disturbance—are mostly distributed along the Andes and in Atlantic Forest, with the greatest concentration in Ecuador. Both the Andes and Atlantic Forest are known hotspots for other faunal and floral components. Contrasting patterns of the older caviomorph and younger sigmodontine radiations underscore the interplay of both historical and ecological factors in determining present-day diversity patterns. PMID:26999278

  9. Endoparasites of Wild Rodents in Southeastern Iran

    PubMed Central

    Nateghpour, Mehdi; Motevalli-Haghi, Afsaneh; Akbarzadeh, Kamran; Akhavan, Amir Ahmad; Mohebali, Mehdi; Mobedi, Iraj; Farivar, Leila

    2015-01-01

    Background: This study was aimed to collect wild rodents for endoparasites determination in some parts of Sistan and Baluchistan Province, southeastern Iran nearby Pakistan and Afghanistan countries. Methods: A total of 100 wild rodents were captured alive with cage traps. Various samples were collected from blood and feces, also impression smear prepared from different organs. The samples were prepared by formalin-ether or stained with Giemsa, after that were examined under microscope. Results: All the caught rodents (47 Tatera indica, 44 Meriones hurriana, 5 Gerbilus nanus and 4 Meriones libycus) were studied for endoparasites emphasizing to their zoonotic aspects. Endoparasites including Spirurida, Hymenolepis diminuta, Hymenolepis nana feraterna, Trichuris trichiura, Skerjabino taenia, Trichostrongylus spp, Entamoeba muris, Chilomastix mesnili and Leishmania spp were parasitologically identified. Conclusion: Among 9 genera or species of the identified parasites at least 5 of them have zoonotic and public health importance. PMID:26114139

  10. Understanding arid environments using fossil rodent middens

    USGS Publications Warehouse

    Pearson, S.; Betancourt, J.L.

    2002-01-01

    American rodent middens have made a more dramatic contribution to understanding past environments and the development of ecological theory than Australian rodent middens. This relates to differences in the natural environment, the landscape histories, the scale and scientific approaches of the researchers. The comparison demonstrates: the power of synoptic perspectives; the value of thorough macrofossil identification in midden analysis and its potential advance in Australia where pollen has dominated analyses, the value of herbaria and reference collections; the potential of environmental databases; the importance of scientific history and 'critical research mass' and; finally, the opportunistic nature of palaeoecological research. ?? 2002 Elsevier Science Ltd.

  11. Chemical carcinogenesis: Too many rodent carcinogens

    SciTech Connect

    Ames, B.N.; Gold, L.S. )

    1990-10-01

    The administration of chemicals at the maximum tolerated dose (MTD) in standard animal cancer tests is postulated to increase cell division (mitogenesis), which in turn increases rates of mutagenesis and thus carcinogenesis. The animal data are consistent with this mechanism, because a high proportion{endash}about half{endash}of all chemicals tested (whether natural or synthetic) are indeed rodent carcinogens. The authors conclude that at the low doses of most human exposures, where cell killing does not occur, the hazards to humans of rodent carcinogens may be much lower than is commonly assumed.

  12. Suprachiasmatic stimulation phase shifts rodent circadian rhythms.

    PubMed

    Rusak, B; Groos, G

    1982-03-12

    The integrity of the suprachiasmatic nuclei (SCN) of the hypothalamus is essential to the expression of normal circadian rhythms in rodents. Electrical stimulation of the SCN caused phase shifts and period changes in the freerunning feeding rhythms of rats and activity rhythms of hamsters. The phase response curve for SCN stimulation appears to parallel that for light pulses. These findings strengthen the hypothesis derived from lesion studies that the SCN are the dominant light-entrained oscillators in the rodent circadian system. PMID:7063851

  13. Object Recognition Memory and the Rodent Hippocampus

    ERIC Educational Resources Information Center

    Broadbent, Nicola J.; Gaskin, Stephane; Squire, Larry R.; Clark, Robert E.

    2010-01-01

    In rodents, the novel object recognition task (NOR) has become a benchmark task for assessing recognition memory. Yet, despite its widespread use, a consensus has not developed about which brain structures are important for task performance. We assessed both the anterograde and retrograde effects of hippocampal lesions on performance in the NOR…

  14. Object Recognition Memory and the Rodent Hippocampus

    ERIC Educational Resources Information Center

    Broadbent, Nicola J.; Gaskin, Stephane; Squire, Larry R.; Clark, Robert E.

    2010-01-01

    In rodents, the novel object recognition task (NOR) has become a benchmark task for assessing recognition memory. Yet, despite its widespread use, a consensus has not developed about which brain structures are important for task performance. We assessed both the anterograde and retrograde effects of hippocampal lesions on performance in the NOR

  15. NEOSPORA CANINUM DETECTED IN WILD RODENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The role of rodents in the epidemiology of neosporosis was investigated by assaying brain tissue of wild mice and rats for Neospora caninum. Both mouse and rat brain tissue were extracted for total DNA, and subjected to two different N. caninum-specific nested PCR assays. A portion of brain tissue...

  16. Arenavirus Diversity and Phylogeography of Mastomys natalensis Rodents, Nigeria

    PubMed Central

    Obadare, Adeoba; Oyeyiola, Akinlabi; Igbokwe, Joseph; Fasogbon, Ayobami; Igbahenah, Felix; Ortsega, Daniel; Asogun, Danny; Umeh, Prince; Vakkai, Innocent; Abejegah, Chukwuyem; Pahlman, Meike; Becker-Ziaja, Beate; Günther, Stephan; Fichet-Calvet, Elisabeth

    2016-01-01

    Mastomys natalensis rodents are natural hosts for Lassa virus (LASV). Detection of LASV in 2 mitochondrial phylogroups of the rodent near the Niger and Benue Rivers in Nigeria underlines the potential for LASV emergence in fresh phylogroups of this rodent. A Mobala-like sequence was also detected in eastern Nigeria.

  17. 7 CFR 58.247 - Insect and rodent control program.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Insect and rodent control program. 58.247 Section 58... Service 1 Operations and Operating Procedures 58.247 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control program...

  18. 7 CFR 58.247 - Insect and rodent control program.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Insect and rodent control program. 58.247 Section 58... Service 1 Operations and Operating Procedures 58.247 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control program...

  19. 20 CFR 654.415 - Insect and rodent control.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Insect and rodent control. 654.415 Section 654.415 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR SPECIAL... Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other vermin....

  20. 7 CFR 58.247 - Insect and rodent control program.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Insect and rodent control program. 58.247 Section 58... Service 1 Operations and Operating Procedures 58.247 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control program...

  1. 7 CFR 58.147 - Insect and rodent control program.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Insect and rodent control program. 58.147 Section 58... Service 1 Operations and Operating Procedures 58.147 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control...

  2. 7 CFR 58.147 - Insect and rodent control program.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Insect and rodent control program. 58.147 Section 58... Service 1 Operations and Operating Procedures 58.147 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control...

  3. 20 CFR 654.415 - Insect and rodent control.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 3 2014-04-01 2014-04-01 false Insect and rodent control. 654.415 Section 654.415 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR SPECIAL... Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other vermin....

  4. 7 CFR 58.147 - Insect and rodent control program.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Insect and rodent control program. 58.147 Section 58... Service 1 Operations and Operating Procedures 58.147 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control...

  5. 7 CFR 58.247 - Insect and rodent control program.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Insect and rodent control program. 58.247 Section 58... Service 1 Operations and Operating Procedures 58.247 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control program...

  6. 20 CFR 654.415 - Insect and rodent control.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 3 2013-04-01 2013-04-01 false Insect and rodent control. 654.415 Section 654.415 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR SPECIAL... Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other vermin....

  7. 7 CFR 58.147 - Insect and rodent control program.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Insect and rodent control program. 58.147 Section 58... Service 1 Operations and Operating Procedures 58.147 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control...

  8. 20 CFR 654.415 - Insect and rodent control.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Insect and rodent control. 654.415 Section 654.415 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR SPECIAL... Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other vermin....

  9. 20 CFR 654.415 - Insect and rodent control.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Insect and rodent control. 654.415 Section 654.415 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR SPECIAL... Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other vermin....

  10. 7 CFR 58.247 - Insect and rodent control program.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Insect and rodent control program. 58.247 Section 58... Service 1 Operations and Operating Procedures § 58.247 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control program...

  11. 7 CFR 58.147 - Insect and rodent control program.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Insect and rodent control program. 58.147 Section 58... Service 1 Operations and Operating Procedures § 58.147 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control...

  12. Arenavirus Diversity and Phylogeography of Mastomys natalensis Rodents, Nigeria.

    PubMed

    Olayemi, Ayodeji; Obadare, Adeoba; Oyeyiola, Akinlabi; Igbokwe, Joseph; Fasogbon, Ayobami; Igbahenah, Felix; Ortsega, Daniel; Asogun, Danny; Umeh, Prince; Vakkai, Innocent; Abejegah, Chukwuyem; Pahlman, Meike; Becker-Ziaja, Beate; Günther, Stephan; Fichet-Calvet, Elisabeth

    2016-04-01

    Mastomys natalensis rodents are natural hosts for Lassa virus (LASV). Detection of LASV in 2 mitochondrial phylogroups of the rodent near the Niger and Benue Rivers in Nigeria underlines the potential for LASV emergence in fresh phylogroups of this rodent. A Mobala-like sequence was also detected in eastern Nigeria. PMID:26982388

  13. Tropical Convection's Roles in Tropical Tropopause Cirrus

    NASA Technical Reports Server (NTRS)

    Boehm, Matthew T.; Starr, David OC.; Verlinde, Johannes; Lee, Sukyoung

    2002-01-01

    Remote sensing observations reveal the frequent occurrence of tropopause cirrus, thin cirrus layers located near the tropical cold-point tropopause. Here, we present a theory in which tropical convection plays several important roles in tropopause cirrus formation. First, tropical convection is the primary means by which the moisture required for tropopause cirrus formation is transported into the upper troposphere. However, previous studies suggest that this convection rarely penetrates to the altitudes at which tropopause cirrus layers are observed, suggesting that additional vertical moisture transport is required to explain tropopause cirrus formation. We propose a mechanism for explaining this transport in which tropical convection plays the key role. According to this hypothesis, the transport is accomplished by meridional circulations that develop within the tropopause transition layer (TTL) in response to momentum transport by Rossby waves generated by tropical convection. Results of a series of global scale model runs designed to test this hypothesis will be presented. In addition, reanalyses vertical velocity data will be examined for evidence of the expected correlation between large-scale rising motion within the TTL and tropical convection. Once moisture is present near the cold-point tropopause, large-scale cooling is required to initiate tropopause cirrus formation. One source of this cooling is stratospheric tropical waves induced by tropical convection, as we will show using a time series of radiosonde temperature data superimposed with data on cloud occurrence from the DOE ARM Nauru99 field experiment. Observations of the global characteristics of these waves from a longer time series of reanalysis data will also be presented.

  14. Tropical Convection's Roles in Tropical Tropopause Cirrus

    NASA Astrophysics Data System (ADS)

    Boehm, M. T.; Starr, D. O.; Verlinde, J.; Lee, S.

    2002-05-01

    Remote sensing observations reveal the frequent occurrence of tropopause cirrus, thin cirrus layers located near the tropical cold-point tropopause. Here, we present a theory in which tropical convection plays several important roles in tropopause cirrus formation. First, tropical convection is the primary means by which the moisture required for tropopause cirrus formation is transported into the upper troposphere. However, previous studies suggest that this convection rarely penetrates to the altitudes at which tropopause cirrus layers are observed, suggesting that additional vertical moisture transport is required to explain tropopause cirrus formation. We propose a mechanism for explaining this transport in which tropical convection plays the key role. According to this hypothesis, the transport is accomplished by meridional circulations that develop within the tropopause transition layer in response to momentum transport by Rossby waves generated by tropical convection. Results of a series of global scale model runs designed to test this hypothesis will be presented. In addition, reanalyses vertical velocity data will be examined for evidence of the expected correlation between large-scale rising motion within the TTL and tropical convection. Once moisture is present near the cold-point tropopause, large-scale cooling is required to initiate tropopause cirrus formation. One source of this cooling is stratospheric tropical waves induced by tropical convection, as we will show using a time series of radiosonde temperature data superimposed with data on cloud occurrence from the DOE ARM Nauru99 field experiment. Observations of the global characteristics of these waves from a longer time series of reanalysis data will also be presented.

  15. Bats and Rodents Shape Mammalian Retroviral Phylogeny.

    PubMed

    Cui, Jie; Tachedjian, Gilda; Wang, Lin-Fa

    2015-01-01

    Endogenous retroviruses (ERVs) represent past retroviral infections and accordingly can provide an ideal framework to infer virus-host interaction over their evolutionary history. In this study, we target high quality Pol sequences from 7,994 Class I and 8,119 Class II ERVs from 69 mammalian genomes and surprisingly find that retroviruses harbored by bats and rodents combined occupy the major phylogenetic diversity of both classes. By analyzing transmission patterns of 30 well-defined ERV clades, we corroborate the previously published observation that rodents are more competent as originators of mammalian retroviruses and reveal that bats are more capable of receiving retroviruses from non-bat mammalian origins. The powerful retroviral hosting ability of bats is further supported by a detailed analysis revealing that the novel bat gammaretrovirus, Rhinolophus ferrumequinum retrovirus, likely originated from tree shrews. Taken together, this study advances our understanding of host-shaped mammalian retroviral evolution in general. PMID:26548564

  16. Rodent reservoirs of future zoonotic diseases.

    PubMed

    Han, Barbara A; Schmidt, John Paul; Bowden, Sarah E; Drake, John M

    2015-06-01

    The increasing frequency of zoonotic disease events underscores a need to develop forecasting tools toward a more preemptive approach to outbreak investigation. We apply machine learning to data describing the traits and zoonotic pathogen diversity of the most speciose group of mammals, the rodents, which also comprise a disproportionate number of zoonotic disease reservoirs. Our models predict reservoir status in this group with over 90% accuracy, identifying species with high probabilities of harboring undiscovered zoonotic pathogens based on trait profiles that may serve as rules of thumb to distinguish reservoirs from nonreservoir species. Key predictors of zoonotic reservoirs include biogeographical properties, such as range size, as well as intrinsic host traits associated with lifetime reproductive output. Predicted hotspots of novel rodent reservoir diversity occur in the Middle East and Central Asia and the Midwestern United States. PMID:26038558

  17. Bats and Rodents Shape Mammalian Retroviral Phylogeny

    PubMed Central

    Cui, Jie; Tachedjian, Gilda; Wang, Lin-Fa

    2015-01-01

    Endogenous retroviruses (ERVs) represent past retroviral infections and accordingly can provide an ideal framework to infer virus-host interaction over their evolutionary history. In this study, we target high quality Pol sequences from 7,994 Class I and 8,119 Class II ERVs from 69 mammalian genomes and surprisingly find that retroviruses harbored by bats and rodents combined occupy the major phylogenetic diversity of both classes. By analyzing transmission patterns of 30 well-defined ERV clades, we corroborate the previously published observation that rodents are more competent as originators of mammalian retroviruses and reveal that bats are more capable of receiving retroviruses from non-bat mammalian origins. The powerful retroviral hosting ability of bats is further supported by a detailed analysis revealing that the novel bat gammaretrovirus, Rhinolophus ferrumequinum retrovirus, likely originated from tree shrews. Taken together, this study advances our understanding of host-shaped mammalian retroviral evolution in general. PMID:26548564

  18. Tropical pulmonary diseases.

    PubMed

    Bovornkitti, S

    1996-03-01

    The term 'tropical' refers to the region of the Earth lying between the Tropic of Cancer and the Tropic of Capricorn. Located between these equatorial parallels demarcating the Torrid Zone are several underdeveloped and developing countries: Thailand, the Philippines, Malaysia, Singapore, Indonesia, southern India, Sri Lanka, Brazil, Cuba, Ethiopia, Sudan and Nigeria, to name but a few considered to be 'tropical'. The climate in most of these countries is characterized by high temperatures and high humidity. The tropical climate and general state of socio-economic underdevelopment in such countries provide an ideal environment for pathogenic organisms, their vectors and intermediate hosts to flourish. Furthermore, the cultural habits and educational background of the people living in such countries expose them to pathogens and, when these people become infected, they readily become reservoirs for, or carriers of, those organisms. Ultimately, the adverse socioeconomic conditions of underdeveloped countries impede attempts to eradicate or control tropical diseases. PMID:9432400

  19. Evolution of the spermatozoon in muroid rodents.

    PubMed

    Breed, William G

    2005-09-01

    In the rodent superfamily Muroidea, a model for the evolution of sperm form has been proposed in which it is suggested that a hook-shaped sperm head and long tail evolved from a more simple, nonhooked head and short tail in several different subfamilies. To test this model the shape of the sperm head, with particular emphasis on its apical region, and length of sperm tail were matched to a recent phylogeny based on the nucleotide sequence of several protein-coding nuclear genes from 3 families and 10 subfamilies of muroid rodents. Data from the two other myomorph superfamilies, the Dipodoidea and kangaroo rats in the Geomyoidea, were used for an outgroup comparison. In most species in all 10 muroid subfamilies, apart from in the Murinae, the sperm head has a long rostral hook largely composed of acrosomal material, although its length and cross-sectional shape vary across the various subfamilies. Nevertheless, in a few species of various lineages a very different sperm morphology occurs in which an apical hook is lacking. In the outgroups the three species of dipodid rodents have a sperm head that lacks a hook, whereas in the heteromyids an acrosome-containing apical hook is present. It is concluded that, as the hook-shaped sperm head and long sperm tail occur across the muroid subfamilies, as well as in the heteromyid rodents, it is likely to be the ancestral condition within each of the subfamilies with the various forms of nonhooked sperm heads, that are sometimes associated with short tails, being highly derived states. These findings thus argue against a repeated evolution in various muroid lineages of a complex, hook-shaped sperm head and long sperm tail from a more simple, nonhooked sperm head and short tail. An alternative proposal for the evolution of sperm form within the Muroidea is presented in the light of these data. PMID:16037955

  20. Evidence for Novel Hepaciviruses in Rodents

    PubMed Central

    Drexler, Jan Felix; Corman, Victor Max; Mller, Marcel Alexander; Lukashev, Alexander N.; Gmyl, Anatoly; Coutard, Bruno; Adam, Alexander; Ritz, Daniel; Leijten, Lonneke M.; van Riel, Debby; Kallies, Rene; Klose, Stefan M.; Gloza-Rausch, Florian; Binger, Tabea; Annan, Augustina; Adu-Sarkodie, Yaw; Oppong, Samuel; Bourgarel, Mathieu; Rupp, Daniel; Hoffmann, Bernd; Schlegel, Mathias; Kmmerer, Beate M.; Krger, Detlev H.; Schmidt-Chanasit, Jonas; Setin, Alvaro Aguilar; Cottontail, Veronika M.; Hemachudha, Thiravat; Wacharapluesadee, Supaporn; Osterrieder, Klaus; Bartenschlager, Ralf; Matthee, Sonja; Beer, Martin; Kuiken, Thijs; Reusken, Chantal; Leroy, Eric M.; Ulrich, Rainer G.; Drosten, Christian

    2013-01-01

    Hepatitis C virus (HCV) is among the most relevant causes of liver cirrhosis and hepatocellular carcinoma. Research is complicated by a lack of accessible small animal models. The systematic investigation of viruses of small mammals could guide efforts to establish such models, while providing insight into viral evolutionary biology. We have assembled the so-far largest collection of small-mammal samples from around the world, qualified to be screened for bloodborne viruses, including sera and organs from 4,770 rodents (41 species); and sera from 2,939 bats (51 species). Three highly divergent rodent hepacivirus clades were detected in 27 (1.8%) of 1,465 European bank voles (Myodes glareolus) and 10 (1.9%) of 518 South African four-striped mice (Rhabdomys pumilio). Bats showed anti-HCV immunoblot reactivities but no virus detection, although the genetic relatedness suggested by the serologic results should have enabled RNA detection using the broadly reactive PCR assays developed for this study. 210 horses and 858 cats and dogs were tested, yielding further horse-associated hepaciviruses but none in dogs or cats. The rodent viruses were equidistant to HCV, exceeding by far the diversity of HCV and the canine/equine hepaciviruses taken together. Five full genomes were sequenced, representing all viral lineages. Salient genome features and distance criteria supported classification of all viruses as hepaciviruses. Quantitative RT-PCR, RNA in-situ hybridisation, and histopathology suggested hepatic tropism with liver inflammation resembling hepatitis C. Recombinant serology for two distinct hepacivirus lineages in 97 bank voles identified seroprevalence rates of 8.3 and 12.4%, respectively. Antibodies in bank vole sera neither cross-reacted with HCV, nor the heterologous bank vole hepacivirus. Co-occurrence of RNA and antibodies was found in 3 of 57 PCR-positive bank vole sera (5.3%). Our data enable new hypotheses regarding HCV evolution and encourage efforts to develop rodent surrogate models for HCV. PMID:23818848

  1. Geometric Morphometrics of Rodent Sperm Head Shape

    PubMed Central

    Varea Snchez, Mara; Bastir, Markus; Roldan, Eduardo R. S.

    2013-01-01

    Mammalian spermatozoa, particularly those of rodent species, are extremely complex cells and differ greatly in form and dimensions. Thus, characterization of sperm size and, particularly, sperm shape represents a major challenge. No consensus exists on a method to objectively assess size and shape of spermatozoa. In this study we apply the principles of geometric morphometrics to analyze rodent sperm head morphology and compare them with two traditional morphometry methods, that is, measurements of linear dimensions and dimensions-derived parameters calculated using formulae employed in sperm morphometry assessments. Our results show that geometric morphometrics clearly identifies shape differences among rodent spermatozoa. It is also capable of discriminating between size and shape and to analyze these two variables separately. Thus, it provides an accurate method to assess sperm head shape. Furthermore, it can identify which sperm morphology traits differ between species, such as the protrusion or retraction of the base of the head, the orientation and relative position of the site of flagellum insertion, the degree of curvature of the hook, and other distinct anatomical features and appendices. We envisage that the use of geometric morphometrics may have a major impact on future studies focused on the characterization of sperm head formation, diversity of sperm head shape among species (and underlying evolutionary forces), the effects of reprotoxicants on changes in cell shape, and phenotyping of genetically-modified individuals. PMID:24312234

  2. Rodent models for compulsive alcohol intake.

    PubMed

    Hopf, F Woodward; Lesscher, Heidi M B

    2014-05-01

    Continued seeking and drinking of alcohol despite adverse legal, health, economic, and societal consequences is a central hallmark of human alcohol use disorders. This compulsive drive for alcohol, defined by resistance to adverse and deleterious consequences, represents a major challenge when attempting to treat alcoholism clinically. Thus, there has long been interest in developing pre-clinical rodent models for the compulsive drug use that characterizes drug addiction. Here, we review recent studies that have attempted to model compulsive aspects of alcohol and cocaine intake in rodents, and consider technical and conceptual issues that need to be addressed when trying to recapitulate compulsive aspects of human addiction. Aversion-resistant alcohol intake has been examined by pairing intake or seeking with the bitter tastant quinine or with footshock, and exciting recent work has used these models to identify neuroadaptations in the amygdala, cortex, and striatal regions that promote compulsive intake. Thus, rodent models do seem to reflect important aspects of compulsive drives that sustain human addiction, and will likely provide critical insights into the molecular and circuit underpinnings of aversion-resistant intake as well as novel therapeutic interventions for compulsive aspects of addiction. PMID:24731992

  3. Rodent models of polycystic ovary syndrome.

    PubMed

    McNeilly, Alan S; Duncan, W Colin

    2013-07-01

    Rodents are clearly valuable models for assessing disruption of fertility. The effects of different steroid treatments at different stages of reproductive life through from fetal to adult have been assessed for effects on fertility, ovarian morphology, hypothalamic-pituitary function or metabolic consequences. The results show that steroid treatments do disrupt fertility in many cases, but the underlying mechanisms are complicated by the effects of the different treatments at multiple sites. As models for PCOS at the ovarian level however, there are a number of problems particularly related to the fact that rodents are multi-ovular species. Apart from an absence of ovulation and corpora lutea, many of the different steroid regimes result in an increase in large atretic, or cystic follicles that do not parallel PCOS in women. Indeed a number of treatments are given at times when they will cause disruption of the positive feedback effects of estradiol, thus blocking ovulation in adult life. The resulting ovarian morphology thus appears to be like that of PCOS but is in fact not a clear mimic. This review of the various studies highlights parallels and problems with the use of rodents to study the mechanisms underlying the development of PCOS in women. PMID:23098676

  4. TROPICAL SPIDERWORT - AN INTRODUCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropical spiderwort (also known as Benghal dayflower) has gone from relative obscurity as a roadside curiosity to troublesome weed with widespread economic impact in Georgia in less than 10 years. South Georgia and Florida are currently plagued by tropical spiderwort, but isolated populations have ...

  5. Rodents and Risk in the Mekong Delta of Vietnam: Seroprevalence of Selected Zoonotic Viruses in Rodents and Humans

    PubMed Central

    Van Cuong, Nguyen; Carrique-Mas, Juan; Vo Be, Hien; An, Nguyen Ngoc; Tue, Ngo Tri; Anh, Nguyet Lam; Anh, Pham Hong; Phuc, Nguyen The; Baker, Stephen; Voutilainen, Liina; Jskelinen, Anne; Huhtamo, Eili; Utriainen, Mira; Sironen, Tarja; Vaheri, Antti; Henttonen, Heikki; Vapalahti, Olli; Chaval, Yannick

    2015-01-01

    Abstract In the Mekong Delta in southern Vietnam, rats are commonly traded in wet markets and sold live for food consumption. We investigated seroprevalence to selected groups of rodent-borne viruses among human populations with high levels of animal exposure and among co-located rodent populations. The indirect fluorescence antibody test (IFAT) was used to determine seropositivity to representative reference strains of hantaviruses (Dobrava virus [DOBV], Seoul virus [SEOV]), cowpox virus, arenaviruses (lymphocytic choriomeningitis virus [LCMV]), flaviviruses (tick-borne encephalitis virus [TBEV]), and rodent parechoviruses (Ljungan virus), using sera from 245 humans living in Dong Thap Province and 275 rodents representing the five common rodent species sold in wet markets and present in peridomestic and farm settings. Combined seropositivity to DOBV and SEOV among the rodents and humans was 6.9% (19/275) and 3.7% (9/245), respectively; 1.1% (3/275) and 4.5% (11/245) to cowpox virus; 5.4% (15/275) and 47.3% (116/245) for TBEV; and exposure to Ljungan virus was 18.8% (46/245) in humans, but 0% in rodents. Very little seroreactivity was observed to LCMV in either rodents (1/275, 0.4%) or humans (2/245, 0.8%). Molecular screening of rodent liver tissues using consensus primers for flaviviruses did not yield any amplicons, whereas molecular screening of rodent lung tissues for hantavirus yielded one hantavirus sequence (SEOV). In summary, these results indicate low to moderate levels of endemic hantavirus circulation, possible circulation of a flavivirus in rodent reservoirs, and the first available data on human exposures to parechoviruses in Vietnam. Although the current evidence suggests only limited exposure of humans to known rodent-borne diseases, further research is warranted to assess public health implications of the rodent trade. PMID:25629782

  6. Rodents and risk in the Mekong Delta of Vietnam: seroprevalence of selected zoonotic viruses in rodents and humans.

    PubMed

    Van Cuong, Nguyen; Carrique-Mas, Juan; Vo Be, Hien; An, Nguyen Ngoc; Tue, Ngo Tri; Anh, Nguyet Lam; Anh, Pham Hong; Phuc, Nguyen The; Baker, Stephen; Voutilainen, Liina; Jskelinen, Anne; Huhtamo, Eili; Utriainen, Mira; Sironen, Tarja; Vaheri, Antti; Henttonen, Heikki; Vapalahti, Olli; Chaval, Yannick; Morand, Serge; Bryant, Juliet E

    2015-01-01

    In the Mekong Delta in southern Vietnam, rats are commonly traded in wet markets and sold live for food consumption. We investigated seroprevalence to selected groups of rodent-borne viruses among human populations with high levels of animal exposure and among co-located rodent populations. The indirect fluorescence antibody test (IFAT) was used to determine seropositivity to representative reference strains of hantaviruses (Dobrava virus [DOBV], Seoul virus [SEOV]), cowpox virus, arenaviruses (lymphocytic choriomeningitis virus [LCMV]), flaviviruses (tick-borne encephalitis virus [TBEV]), and rodent parechoviruses (Ljungan virus), using sera from 245 humans living in Dong Thap Province and 275 rodents representing the five common rodent species sold in wet markets and present in peridomestic and farm settings. Combined seropositivity to DOBV and SEOV among the rodents and humans was 6.9% (19/275) and 3.7% (9/245), respectively; 1.1% (3/275) and 4.5% (11/245) to cowpox virus; 5.4% (15/275) and 47.3% (116/245) for TBEV; and exposure to Ljungan virus was 18.8% (46/245) in humans, but 0% in rodents. Very little seroreactivity was observed to LCMV in either rodents (1/275, 0.4%) or humans (2/245, 0.8%). Molecular screening of rodent liver tissues using consensus primers for flaviviruses did not yield any amplicons, whereas molecular screening of rodent lung tissues for hantavirus yielded one hantavirus sequence (SEOV). In summary, these results indicate low to moderate levels of endemic hantavirus circulation, possible circulation of a flavivirus in rodent reservoirs, and the first available data on human exposures to parechoviruses in Vietnam. Although the current evidence suggests only limited exposure of humans to known rodent-borne diseases, further research is warranted to assess public health implications of the rodent trade. PMID:25629782

  7. [Vacation and tropical dermatoses].

    PubMed

    Fischer, M; Reinel, D

    2012-05-01

    Besides fever and diarrhea, skin diseases are the third most common cause of morbidity in returning travelers after a stay in a tropical country. Approximately one- quarter of these dermatological symptoms can be referred to a classical tropical disease. The majority are of infectious origin. Often only the clinical appearance leads to the diagnosis of a tropical disease as myiasis, cutaneous larva migrans, tungiasis or cutaneous leishmaniasis. Not infrequently the dermatological symptoms lead to the diagnosis of a primarily systemic tropical disease. For example, an eschar with or without a rash might lead to the diagnosis of a South African tick bite fever caused by Rickettsia africae days before serology may turn positive. Less common tropical skin diseases such as lymphatic filariasis and loiasis need to be considered in returning long-term travelers and immigrants. PMID:22532262

  8. Tropical Pacific moisture variability

    NASA Technical Reports Server (NTRS)

    Mcguirk, James P.

    1991-01-01

    The research objectives were to describe synoptic scale variability of moisture over the tropical Pacific Ocean and the systems leading to this variability, to implement satellite analysis procedures to accomplish that objective, to incorporate additional satellite information into operational analysis/forecast systems at the National Meteorological Center (NMC), and to synthesize knowledge gained from satellite observations through diagnosis and numerical models. In the past year, three significant satellite data analysis tasks were accomplished: comparisons for upwelling radiance fields for 1983 and 1984 were completed for the purpose of testing the sensitivity of water vapor/greenhouse feedback to local sea surface temperature variations; the interaction between tropical plumes, wave features over Central America, traveling waves in the upper tropospheric tropics, and the tropical interseasonal oscillation was examined; and planning and early efforts on the construction of a model and the infrared based climatology of daily precipitable water was completed. Research on tropical plume mechanisms included is briefly discussed.

  9. Leptospira and rodents in Cambodia: environmental determinants of infection.

    PubMed

    Ivanova, Svilena; Herbreteau, Vincent; Blasdell, Kim; Chaval, Yannick; Buchy, Philippe; Guillard, Bertrand; Morand, Serge

    2012-06-01

    We investigated infection of rodents and shrews by Leptospira spp. in two localities of Cambodia (Veal Renh, Kaev Seima) and in four types of habitat (forests, non-flooded lands, lowland rain-fed paddy fields, houses) during the wet and the dry seasons. Habitat preference was common, and rodent and shrew species were found only in houses or in rain-fed paddy fields or in forests. Among 649 small mammals trapped belonging to 12 rodent species and 1 shrew species, 71 of 642 animals tested were carriers of Leptospira according to the 16S ribosomal RNA marker used. Rodent infection was higher in low-slope locations, corresponding to rain-fed paddy fields, especially in the rainy season and in Kaev Seima. Rodents (Rattus exulans) and shrews (Suncus murinus) inhabiting households showed significantly low levels of infections, whereas rodents living in and near to forests (shrubby wasteland, orchards) showed high levels of infection. PMID:22665613

  10. Leptospira and Rodents in Cambodia: Environmental Determinants of Infection

    PubMed Central

    Ivanova, Svilena; Herbreteau, Vincent; Blasdell, Kim; Chaval, Yannick; Buchy, Philippe; Guillard, Bertrand; Morand, Serge

    2012-01-01

    We investigated infection of rodents and shrews by Leptospira spp. in two localities of Cambodia (Veal Renh, Kaev Seima) and in four types of habitat (forests, non-flooded lands, lowland rain-fed paddy fields, houses) during the wet and the dry seasons. Habitat preference was common, and rodent and shrew species were found only in houses or in rain-fed paddy fields or in forests. Among 649 small mammals trapped belonging to 12 rodent species and 1 shrew species, 71 of 642 animals tested were carriers of Leptospira according to the 16S ribosomal RNA marker used. Rodent infection was higher in low-slope locations, corresponding to rain-fed paddy fields, especially in the rainy season and in Kaev Seima. Rodents (Rattus exulans) and shrews (Suncus murinus) inhabiting households showed significantly low levels of infections, whereas rodents living in and near to forests (shrubby wasteland, orchards) showed high levels of infection. PMID:22665613

  11. Clinical aspects of rodent dental anatomy.

    PubMed

    Crossley, D A

    1995-12-01

    The order Rodentia is vast, encompassing a large number of species with significant anatomical variations developed during natural adaptation to differing habitats. Many veterinarians have little knowledge of the anatomy of species other than the commoner domestic large herbivores and small carnivores. Clinicians require a basic knowledge of the relevant anatomy of species they are likely to be asked to treat. This article provides sufficient working knowledge of the oral and dental anatomy of those rodents commonly kept as pets to enable veterinarians to interpret clinical and radiographic findings when investigating suspected dental disease. PMID:9693638

  12. A program for simulated rodent surgical training.

    PubMed

    Stevens, Carol A; Dey, Nicholas D

    2007-10-01

    For the inexperienced individual, learning surgical techniques can be taxing. The authors developed a rodent surgery dry lab training program to assist educational and research institutions in providing low-stress training for basic surgical techniques using handmade, cost-effective simulation models. The program not only helps students develop essential skills in basic surgery, but also fulfills the mandate of the 3Rs by allowing students to repeatedly practice and refine their skills on models rather than live animals. This type of training is a valuable tool in bridging the gap between computer training and training with live animals. PMID:17885661

  13. Control of Domestic Rats & Mice, Training Guide--Rodent Control Series.

    ERIC Educational Resources Information Center

    Bjornson, Bayard F.; And Others

    As one booklet in a series on rodent control, this training guide has been developed to assist administrators, rodent-control operators, and others responsible for rodent-control operations in the training of employees in this field. Topics covered include rodents and human welfare, description and habits of domestic rats and mice, rodent-borne

  14. Rodent Models of Amyotrophic Lateral Sclerosis.

    PubMed

    Philips, Thomas; Rothstein, Jeffrey D

    2015-01-01

    Amyotrophic Lateral Sclerosis (ALS) is a motor neuron disease affecting upper and lower motor neurons in the central nervous system. Patients with ALS develop extensive muscle wasting and atrophy leading to paralysis and death 3 to 5 years after disease onset. The condition may be familial (fALS 10%) or sporadic ALS (sALS, 90%). The large majority of fALS cases are due to genetic mutations in the Superoxide dismutase 1 gene (SOD1, 15% of fALS) and repeat nucleotide expansions in the gene encoding C9ORF72 (∼ 40% to 50% of fALS and ∼ 10% of sALS). Studies suggest that ALS is mediated through aberrant protein homeostasis (i.e., ER stress and autophagy) and/or changes in RNA processing (as in all non-SOD1-mediated ALS). In all of these cases, animal models suggest that the disorder is mediated non-cell autonomously, i.e., not only motor neurons are involved, but glial cells including microglia, astrocytes, and oligodendrocytes, and other neuronal subpopulations are also implicated in the pathogenesis. Provided in this unit is a review of ALS rodent models, including discussion of their relative advantages and disadvantages. Emphasis is placed on correlating the model phenotype with the human condition and the utility of the model for defining the disease process. Information is also presented on RNA processing studies in ALS research, with particular emphasis on the newest ALS rodent models. PMID:26344214

  15. Hunting, Food Preparation, and Consumption of Rodents in Lao PDR

    PubMed Central

    Suwannarong, Kanokwan; Chapman, Robert S.; Lantican, Cecile; Michaelides, Tula; Zimicki, Susan

    2015-01-01

    A cross-sectional study was conducted in 29 villages of Khamkeuth District in Bolikhamxay Province in the Lao PDR during March to May 2013. The study aimed to determine the characteristics associated with rodent consumption and related behaviors among different ethnic groups, ages, and genders. Five-hundred-eighty-four (584) males and females from 18-50 years of age participated in this study. Half of them were Hmong (292, 50%) while 152 respondents were Lao-Tai (26%) or other ethnic groups (140, 24%). Most of the respondents (79.5%) had farming as their main occupation. Prevalences of the studied outcomes were high: 39.9 for hunting or capturing rodents in the previous year, 77.7% for preparing rodents as food, and 86.3% for rodent consumption. Multivariable logistic regression analysis showed that likelihood of these types of rodent contact was more consistently associated with behavioral factors (gathering things from the forest and elsewhere, cultivation-related activities, and taking measures to prevent rodent-borne disease) than with socio-demographic, environmental, or cultural factors. The strongest associations were observed for gathering things; these associations were consistently positive and statistically significant. Although this study did not directly assess rodent-borne zoonosis risk, we believe that study findings raise concern that such risk may be substantial in the study area and other similar areas. Further epidemiological studies on the association between rodent-borne disease infection and rodent hunting, preparation for food, and consumption are recommended. Moreover, further studies are needed on the association between these potential exposure factors (i.e., rodent hunting, preparation for food, and consumption) and rodent-borne infections, especially among ethnic groups like the Hmong in Lao PDR and those in neighboring countries with similar socio-demographic, environmental, behavioral and cultural contexts. PMID:26196134

  16. Deforestation in the Tropics

    SciTech Connect

    Repetto, R. )

    1990-04-01

    Government policies that encourage exploitation--in particular excessive logging and clearing for ranches and farms--are largely to blame for the accelerating destruction of tropical forests. This paper surveys the problem in detail and briefly recommends potential solutions.

  17. [Tropical climate pathology].

    PubMed

    Besancenot, J P

    1997-01-01

    In addition to being a determinant factor for the development of infectious and parasitic diseases, tropical weather conditions can have harmful effects for the human organism different from those of temperate climates. Adverse effects can result from aggressive environmental factors such as ultraviolet radiation, extreme heat, abrupt changes in temperature, and tropical storms. In weather-sensitive subjects, exposure to tropical conditions increases the risk of acute reactions including ischemic heart disease, asthma attacks, and kidney stones. Adverse effects can be enhanced by suddenness of change in climate as underlined by the stress experienced by air travelers. In practice it is important to recognize that different tropical climates have different effects on health. Intertropical climates range from dry and rainy areas to plains and mountain areas. Knowledge of the concepts of climatopathology is necessary to advise patients on the choice of destination and the most favorable period for travel. PMID:9612744

  18. RODENT DAMAGE ON SURFACE DRIP IRRIGATION TUBING IN PEANUT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface drip (SD) irrigation of field crops has been gaining interest in the farming community. However, rodent damage is one of the major drawbacks for SD acceptance. This research documents the cost of repairing drip tubing and effectiveness of several rodent control methods. Four sites were used ...

  19. Recent isolations of Lassa virus from Nigerian rodents

    PubMed Central

    Wulff, Herta; Fabiyi, A.; Monath, T. P.

    1975-01-01

    Rodents were trapped in the Benue-Plateau and North-Eastern States of Nigeria where Lassa fever had been reported in previous years. Eight Lassa virus strains were isolated from tissues and blood of rodents identified in the field as being of 3 different species: Mastomys natalensis, Rattus rattus, and Mus minutoides. All the infected rodents were collected in village habitats. These isolations indicate the presence of Lassa virus in wild rodents in Nigeria during periods when no human infections were evident. Prior studies in Sierra Leone have indicated that a single rodent species, M. natalensis, may be the important reservoir host of Lassa virus. Since the present study indicates that other rodent species may be involved as well, the ecology of Lassa virus may be more complicated than was heretofore supposed. In view of the importance of determining the geographic and species range of rodent hosts of Lassa virus, and because of the problems inherent in rodent identification under austere field conditions, it is urgent that further studies be conducted in the same areas of Nigeria to confirm these findings. PMID:1085216

  20. Visual Landmarks Facilitate Rodent Spatial Navigation in Virtual Reality Environments

    ERIC Educational Resources Information Center

    Youngstrom, Isaac A.; Strowbridge, Ben W.

    2012-01-01

    Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain

  1. PREDICTIVE SIMULATION MODELING FOR ANTIANDROGEN IMPACTS ON RODENT PROSTATE

    EPA Science Inventory

    Predictive simulation modeling for antiandrogen impacts on rodent prostate
    HA Barton1, RW Setzer1, LK Potter1,2
    1US EPA, ORD, NHEERL, ETD, PKB, Research Triangle Park, NC and 2Curriculum in Toxicology, UNC, Chapel Hill, NC

    Changes in rodent prostate weight and functi...

  2. Vitamin K Contents of Rodent Diets: A Review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adequate nutrient intake is critical in the maintenance of normal physiological activity of rodents in biomedical studies. Vitamin K is an essential nutrient in rodent diets and functions as a cofactor for the y-carboxylation of certain proteins involved in blood coagulation and bone metabolism. Dif...

  3. Visual Landmarks Facilitate Rodent Spatial Navigation in Virtual Reality Environments

    ERIC Educational Resources Information Center

    Youngstrom, Isaac A.; Strowbridge, Ben W.

    2012-01-01

    Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain…

  4. 40 CFR 798.5460 - Rodent heritable translocation assays.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Rodent heritable translocation assays. 798.5460 Section 798.5460 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Genetic Toxicity § 798.5460 Rodent heritable translocation assays. (a)...

  5. Bartonella Infection in Rodents and Their Flea Ectoparasites: An Overview

    PubMed Central

    Gutiérrez, Ricardo; Krasnov, Boris; Morick, Danny; Gottlieb, Yuval; Khokhlova, Irina S.

    2015-01-01

    Abstract Epidemiological studies worldwide have reported a high prevalence and a great diversity of Bartonella species, both in rodents and their flea parasites. The interaction among Bartonella, wild rodents, and fleas reflects a high degree of adaptation among these organisms. Vertical and horizontal efficient Bartonella transmission pathways within flea communities and from fleas to rodents have been documented in competence studies, suggesting that fleas are key players in the transmission of Bartonella to rodents. Exploration of the ecological traits of rodents and their fleas may shed light on the mechanisms used by bartonellae to become established in these organisms. The present review explores the interrelations within the Bartonella–rodent–flea system. The role of the latter two components is emphasized. PMID:25629778

  6. Scatter-Hoarding Rodents Prefer Slightly Astringent Food

    PubMed Central

    Wang, Bo; Chen, Jin

    2011-01-01

    The mutualistic interaction between scatter-hoarding rodents and their seed plants is highly complex yet poorly understood. Plants may benefit from the seed dispersal behavior of rodents, as long as seed consumption is minimized. In parallel, rodents may maximize foraging efficiency and cache high-quality resources for future consumption. Defensive compounds, such as tannins, are thought to be a major mechanism for plant control over rodent behavior. However, previous studies, using naturally occurring seeds, have not provided conclusive evidence supporting this hypothesis. Here, we test the importance of tannin concentrations on the scatter-hoarding behavior of rodents by using an artificial seed system. We combined feeding trials and field observations to examine the overall impact of seed tannin concentrations on rodent behavior and health. We found that rodents favored seeds with an intermediate amount of tannin (∼5%) in the field. Meanwhile, in rodents that were fed a diet with different tannin content, only diets with high tannin content (25%, 15%, and 10%) caused a significant negative influence on rodent survival and health. Significant differences were not found among treatments with tannin levels of 0–5%. In contrast to many existing studies, our results clearly demonstrate that scatter-hoarding rodents prefer slightly ‘astringent’ food. In the co-evolutionary arms race between plants and animals, our results suggest that while tannins may play a significant role in reducing general predation levels by the faunal community, they have no precise control over the behavior of their mutualistic partner. Instead, the two partners appear to have reached an evolutionary point where both parties receive adequate benefits, with the year-to-year outcome being dependent on a wide range of factors beyond the control of either partner. PMID:22046284

  7. Epidemiology of Leptospira Transmitted by Rodents in Southeast Asia

    PubMed Central

    Mielcarek, Mathilde; Tatard, Caroline; Chaval, Yannick; Suputtamongkol, Yupin; Buchy, Philippe; Jittapalapong, Sathaporn; Herbreteau, Vincent; Morand, Serge

    2014-01-01

    Background Leptospirosis is the most common bacterial zoonoses and has been identified as an important emerging global public health problem in Southeast Asia. Rodents are important reservoirs for human leptospirosis, but epidemiological data is lacking. Methodology/Principal Findings We sampled rodents living in different habitats from seven localities distributed across Southeast Asia (Thailand, Lao PDR and Cambodia), between 2009 to 2010. Human isolates were also obtained from localities close to where rodents were sampled. The prevalence of Leptospira infection was assessed by real-time PCR using DNA extracted from rodent kidneys, targeting the lipL32 gene. Sequencing rrs and secY genes, and Multi Locus Variable-number Tandem Repeat (VNTR) analyses were performed on DNA extracted from rat kidneys for Leptospira isolates molecular typing. Four species were detected in rodents, L. borgpetersenii (56% of positive samples), L. interrogans (36%), L. kirschneri (3%) and L. weilli (2%), which were identical to human isolates. Mean prevalence in rodents was approximately 7%, and largely varied across localities and habitats, but not between rodent species. The two most abundant Leptospira species displayed different habitat requirements: L. interrogans was linked to humid habitats (rice fields and forests) while L. borgpetersenii was abundant in both humid and dry habitats (non-floodable lands). Conclusion/Significance L. interrogans and L. borgpetersenii species are widely distributed amongst rodent populations, and strain typing confirmed rodents as reservoirs for human leptospirosis. Differences in habitat requirements for L. interrogans and L. borgpetersenii supported differential transmission modes. In Southeast Asia, human infection risk is not only restricted to activities taking place in wetlands and rice fields as is commonly accepted, but should also include tasks such as forestry work, as well as the hunting and preparation of rodents for consumption, which deserve more attention in future epidemiological studies. PMID:24901706

  8. Oxytocin-dependent consolation behavior in rodents.

    PubMed

    Burkett, J P; Andari, E; Johnson, Z V; Curry, D C; de Waal, F B M; Young, L J

    2016-01-22

    Consolation behavior toward distressed others is common in humans and great apes, yet our ability to explore the biological mechanisms underlying this behavior is limited by its apparent absence in laboratory animals. Here, we provide empirical evidence that a rodent species, the highly social and monogamous prairie vole (Microtus ochrogaster), greatly increases partner-directed grooming toward familiar conspecifics (but not strangers) that have experienced an unobserved stressor, providing social buffering. Prairie voles also match the fear response, anxiety-related behaviors, and corticosterone increase of the stressed cagemate, suggesting an empathy mechanism. Exposure to the stressed cagemate increases activity in the anterior cingulate cortex, and oxytocin receptor antagonist infused into this region abolishes the partner-directed response, showing conserved neural mechanisms between prairie vole and human. PMID:26798013

  9. Intraoperative cerebral blood flow imaging of rodents

    NASA Astrophysics Data System (ADS)

    Li, Hangdao; Li, Yao; Yuan, Lu; Wu, Caihong; Lu, Hongyang; Tong, Shanbao

    2014-09-01

    Intraoperative monitoring of cerebral blood flow (CBF) is of interest to neuroscience researchers, which offers the assessment of hemodynamic responses throughout the process of neurosurgery and provides an early biomarker for surgical guidance. However, intraoperative CBF imaging has been challenging due to animal's motion and position change during the surgery. In this paper, we presented a design of an operation bench integrated with laser speckle contrast imager which enables monitoring of the CBF intraoperatively. With a specially designed stereotaxic frame and imager, we were able to monitor the CBF changes in both hemispheres during the rodent surgery. The rotatable design of the operation plate and implementation of online image registration allow the technician to move the animal without disturbing the CBF imaging during surgery. The performance of the system was tested by middle cerebral artery occlusion model of rats.

  10. Generation of rodent and human osteoblasts

    PubMed Central

    Taylor, Sarah E B; Shah, Mittal; Orriss, Isabel R

    2014-01-01

    This paper describes the isolation, culture and staining of primary osteoblasts from neonatal rodents and human samples. The calvaria and long-bone assays allow direct measurement of bone matrix deposition and mineralisation, as well as producing osteoblasts at defined stages of differentiation for molecular and histological analysis. Culture of human osteoblasts enables cell function to be investigated in targeted patient groups. The described methods will provide a step-by-step guide of what to expect at each stage of the culture and highlight the varied tissue culture conditions required to successfully grow osteoblasts from different sources. A special focus of this paper is the methods used for analysis of bone mineralisation and how to ensure that nonspecific mineral deposition or staining is not quantified. PMID:25396049

  11. Domestic Rodent Control Training Manual: A Training Aid for the Rodent Control Category for Certification of Pesticide Applicators.

    ERIC Educational Resources Information Center

    Childress, William R., Jr.; And Others

    This training manual, designed for training applicants who wish to obtain certification in pesticide application relative to rodent control, covers the following topics: economic factors, public health factors, biological characteristics of domestic rodents, rat and mouse signs, trapping, repellents, poisons, baits, poisoned water, dumps, sewers,…

  12. Domestic Rodent Control Training Manual: A Training Aid for the Rodent Control Category for Certification of Pesticide Applicators.

    ERIC Educational Resources Information Center

    Childress, William R., Jr.; And Others

    This training manual, designed for training applicants who wish to obtain certification in pesticide application relative to rodent control, covers the following topics: economic factors, public health factors, biological characteristics of domestic rodents, rat and mouse signs, trapping, repellents, poisons, baits, poisoned water, dumps, sewers,

  13. Brain acetylcholinesterase activity recovery following acute methyl parathion intoxication in two feral rodent species: comparison to laboratory rodents

    SciTech Connect

    Roberts, D.K.; Silvey, N.J.; Bailey, E.M. Jr.

    1988-07-01

    Widespread use of organophosphorus insecticides (OPs) has produced both acute and chronic intoxication among nontarget organisms. Most such studies have included fish and birds as opposed to mammals. However, numerous OP toxicity studies have been conducted on laboratory rodents creating a temptation to apply this data to feral rodents. Chronic OP exposure has been reported to produce cholinergic adaptation which in turn lowers mortality rates following a subsequent acute anticholinesterase exposure. The relevance that these laboratory rodent studies have on feral rodents is subject to debate. Field studies involving OP exposure among nontarget feral mammals have produced contradictory results. Increased mortality as a result of repeated OP application has been reported. This observation may be of considerable importance to nontarget feral rodent populations due to the repetitive nature of OP application protocols. The ability of feral rodents to recover brain AChE activity (BAA) between OP application intervals undoubtedly promotes their survival. This study investigated and compared BAA recovery following acute oral methyl parathion intoxication among 2 feral rodent species and among 2 common laboratory rodent species.

  14. Automatic cortical thickness analysis on rodent brain

    NASA Astrophysics Data System (ADS)

    Lee, Joohwi; Ehlers, Cindy; Crews, Fulton; Niethammer, Marc; Budin, Francois; Paniagua, Beatriz; Sulik, Kathy; Johns, Josephine; Styner, Martin; Oguz, Ipek

    2011-03-01

    Localized difference in the cortex is one of the most useful morphometric traits in human and animal brain studies. There are many tools and methods already developed to automatically measure and analyze cortical thickness for the human brain. However, these tools cannot be directly applied to rodent brains due to the different scales; even adult rodent brains are 50 to 100 times smaller than humans. This paper describes an algorithm for automatically measuring the cortical thickness of mouse and rat brains. The algorithm consists of three steps: segmentation, thickness measurement, and statistical analysis among experimental groups. The segmentation step provides the neocortex separation from other brain structures and thus is a preprocessing step for the thickness measurement. In the thickness measurement step, the thickness is computed by solving a Laplacian PDE and a transport equation. The Laplacian PDE first creates streamlines as an analogy of cortical columns; the transport equation computes the length of the streamlines. The result is stored as a thickness map over the neocortex surface. For the statistical analysis, it is important to sample thickness at corresponding points. This is achieved by the particle correspondence algorithm which minimizes entropy between dynamically moving sample points called particles. Since the computational cost of the correspondence algorithm may limit the number of corresponding points, we use thin-plate spline based interpolation to increase the number of corresponding sample points. As a driving application, we measured the thickness difference to assess the effects of adolescent intermittent ethanol exposure that persist into adulthood and performed t-test between the control and exposed rat groups. We found significantly differing regions in both hemispheres.

  15. Natural selection and the genetic basis of osmoregulation in heteromyid rodents as revealed by RNA-seq.

    PubMed

    Marra, Nicholas J; Romero, Andrea; DeWoody, J Andrew

    2014-06-01

    One adaptation of ecological and evolutionary interest is the extraordinary ability of desert rodents to retain water during waste production. Much is known regarding the unique kidney physiology of kangaroo rats (Dipodomys spp.) and their ability to retain water during waste production, yet the genetic basis of these physiological adaptations is relatively unknown. Herein, we utilized RNA-seq data to conduct a comparative study to identify osmoregulatory genes expressed in heteromyid rodents. We sequenced kidney tissue from two temperate desert species (Dipodomys spectabilis and Chaetodipus baileyi) from two separate subfamilies of the Heteromyidae and compared these transcriptomes to a tropical mesic species (Heteromys desmarestianus) from a third subfamily. The evolutionary history of these subfamilies provided a robust phylogenetic control that allowed us to separate shared evolutionary history from convergence. Using two methods to detect differential expression (DE), we identified 1890 genes that showed consistent patterns of DE between the arid and mesic species. A three-species reciprocal BLAST analysis revealed 3511 sets of putative orthologues that, upon comparison to known Mus musculus sequences, revealed 323 annotated and full-length genic regions. Selection tests displayed evidence of positive selection (dn/ds > 1) on six genes in the two desert species and remained significant for one of these genes after correction for multiple testing. Thus, our data suggest that both the coding sequence and expression of genes have been shaped by natural selection to provide the genetic architecture for efficient osmoregulation in desert-adapted heteromyid rodents. PMID:24754676

  16. Grey swan tropical cyclones

    NASA Astrophysics Data System (ADS)

    Lin, Ning; Emanuel, Kerry

    2016-01-01

    We define `grey swan’ tropical cyclones as high-impact storms that would not be predicted based on history but may be foreseeable using physical knowledge together with historical data. Here we apply a climatological-hydrodynamic method to estimate grey swan tropical cyclone storm surge threat for three highly vulnerable coastal regions. We identify a potentially large risk in the Persian Gulf, where tropical cyclones have never been recorded, and larger-than-expected threats in Cairns, Australia, and Tampa, Florida. Grey swan tropical cyclones striking Tampa, Cairns and Dubai can generate storm surges of about 6 m, 5.7 m and 4 m, respectively, with estimated annual exceedance probabilities of about 1/10,000. With climate change, these probabilities can increase significantly over the twenty-first century (to 1/3,100-1/1,100 in the middle and 1/2,500-1/700 towards the end of the century for Tampa). Worse grey swan tropical cyclones, inducing surges exceeding 11 m in Tampa and 7 m in Dubai, are also revealed with non-negligible probabilities, especially towards the end of the century.

  17. Structural insights into the rodent CNS via diffusion tensor imaging

    PubMed Central

    Zhang, Jiangyang; Aggarwal, Manisha; Mori, Susumu

    2012-01-01

    Diffusion tensor imaging (DTI) is a useful tool for studying anatomy and pathology in the rodent central nervous system (CNS).The unique tissue contrasts provided by DTI are well suited for monitoring disease progression, studying brain development, and characterizing anatomical phenotypes. Recent technical developments have vastly improved the speed and resolution of rodent DTI. Ongoing research efforts exploring the microstructural basis of DTI signals have provided useful insights into its capabilities to delineate brain structures and detect neuropathology. Significant progress has also been made in combining DTI results with data acquired using other imaging modalities to enhance our understanding of the rodent CNS. PMID:22651954

  18. Tropical cyclone formation

    SciTech Connect

    Montgomery, M.T.; Farrell, B.F. )

    1993-01-15

    The physics of tropical cyclone formation is not well understood, and more is known about the mature hurricane than the formative mechanisms that produce it. It is believed part of the reason for this can be traced to insufficient upper-level atmospheric data. Recent observations suggest that tropical cyclones are initiated by asymmetric interactions associated with migratory upper-level potential vorticity disturbances and low-level disturbances. Favored theories of cyclones formation, however, focus on internal processes associated with cumulus convection and/or air-sea interaction. This work focuses on external mechanisms of cyclone formation and, using both a two- and three-dimensional moist geostrophic momentum model, investigates the role of upper-level potential vorticity disturbances on the formation process. A conceptual model of tropical cyclone formation is proposed, and implications of the theory are discussed. 71 refs., 5 figs., 1 tab.

  19. Tropical Rainfall Measuring Mission

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Tropical rainfall affects the lives and economics of a majority of the Earth's population. Tropical rain systems, such as hurricanes, typhoons, and monsoons, are crucial to sustaining the livelihoods of those living in the tropics. Excess rainfall can cause floods and great property and crop damage, whereas too little rainfall can cause drought and crop failure. The latent heat release during the process of precipitation is a major source of energy that drives the atmospheric circulation. This latent heat can intensify weather systems, affecting weather thousands of kilometers away, thus making tropical rainfall an important indicator of atmospheric circulation and short-term climate change. Tropical forests and the underlying soils are major sources of many of the atmosphere's trace constituents. Together, the forests and the atmosphere act as a water-energy regulating system. Most of the rainfall is returned to the atmosphere through evaporation and transpiration, and the atmospheric trace constituents take part in the recycling process. Hence, the hydrological cycle provides a direct link between tropical rainfall and the global cycles of carbon, nitrogen, and sulfur, all important trace materials for the Earth's system. Because rainfall is such an important component in the interactions between the ocean, atmosphere, land, and the biosphere, accurate measurements of rainfall are crucial to understanding the workings of the Earth-atmosphere system. The large spatial and temporal variability of rainfall systems, however, poses a major challenge to estimating global rainfall. So far, there has been a lack of rain gauge networks, especially over the oceans, which points to satellite measurement as the only means by which global observation of rainfall can be made. The Tropical Rainfall Measuring Mission (TRMM), jointly sponsored by the National Aeronautics and Space Administration (NASA) of the United States and the National Space Development Agency (NASDA) of Japan, provides visible, infrared, and microwave observations of tropical and subtropical rain systems.The satellite observations are complemented by ground radar and rain gauge measurements to validate satellite rain estimation techniques. Goddard Space Flight Center's involvement includes the observatory, four instruments, integration and testing of the observatory, data processing and distribution, and satellite operations. TRMM has a design lifetime of three years. Data generated from TRMM and archived at the GDAAC are useful not only for hydrologists, atmospheric scientists, and climatologists, but also for the health community studying infectious diseases, the ocean research community, and the agricultural community.

  20. Emerging diseases in tropical dermatology.

    PubMed

    High, Whitney A; Bravo, Francisco G

    2007-01-01

    All dermatologists worldwide should have at least passing familiarity with various tropical maladies that generate cutaneous manifestions. In addition to the standard infectious ailments associated with tropical environs, the authors have described herein five "emerging" illnesses that are gaining increasing attention for their capacity to cause human disease in those immigrating from, or traveling to, the tropical and subtropical world. PMID:18159908

  1. Hindlimb unloading rodent model: technical aspects

    NASA Technical Reports Server (NTRS)

    Morey-Holton, Emily R.; Globus, Ruth K.

    2002-01-01

    Since its inception at the National Aeronautics and Space Administration (NASA) Ames Research Center in the mid-1970s, many laboratories around the world have used the rat hindlimb unloading model to simulate weightlessness and to study various aspects of musculoskeletal loading. In this model, the hindlimbs of rodents are elevated to produce a 30 degrees head-down tilt, which results in a cephalad fluid shift and avoids weightbearing by the hindquarters. Although several reviews have described scientific results obtained with this model, this is the first review to focus on the technical aspects of hindlimb unloading. This review includes a history of the technique, a brief comparison with spaceflight data, technical details, extension of the model to mice, and other important technical considerations (e.g., housing, room temperature, unloading angle, the potential need for multiple control groups, age, body weight, the use of the forelimb tissues as internal controls, and when to remove animals from experiments). This paper is intended as a reference for researchers, reviewers of manuscripts, and institutional animal care and use committees. Over 800 references, related to the hindlimb unloading model, can be accessed via the electronic version of this article.

  2. Assessing Spatial Learning and Memory in Rodents

    PubMed Central

    Vorhees, Charles V.; Williams, Michael T.

    2014-01-01

    Maneuvering safely through the environment is central to survival of almost all species. The ability to do this depends on learning and remembering locations. This capacity is encoded in the brain by two systems: one using cues outside the organism (distal cues), allocentric navigation, and one using self-movement, internal cues and nearby proximal cues, egocentric navigation. Allocentric navigation involves the hippocampus, entorhinal cortex, and surrounding structures; in humans this system encodes allocentric, semantic, and episodic memory. This form of memory is assessed in laboratory animals in many ways, but the dominant form of assessment is the Morris water maze (MWM). Egocentric navigation involves the dorsal striatum and connected structures; in humans this system encodes routes and integrated paths and, when overlearned, becomes procedural memory. In this article, several allocentric assessment methods for rodents are reviewed and compared with the MWM. MWM advantages (little training required, no food deprivation, ease of testing, rapid and reliable learning, insensitivity to differences in body weight and appetite, absence of nonperformers, control methods for proximal cue learning, and performance effects) and disadvantages (concern about stress, perhaps not as sensitive for working memory) are discussed. Evidence-based design improvements and testing methods are reviewed for both rats and mice. Experimental factors that apply generally to spatial navigation and to MWM specifically are considered. It is concluded that, on balance, the MWM has more advantages than disadvantages and compares favorably with other allocentric navigation tasks. PMID:25225309

  3. Navigating actions through the rodent parietal cortex

    PubMed Central

    Whitlock, Jonathan R.

    2014-01-01

    The posterior parietal cortex (PPC) participates in a manifold of cognitive functions, including visual attention, working memory, spatial processing, and movement planning. Given the vast interconnectivity of PPC with sensory and motor areas, it is not surprising that neuronal recordings show that PPC often encodes mixtures of spatial information as well as the movements required to reach a goal. Recent work sought to discern the relative strength of spatial vs. motor signaling in PPC by recording single unit activity in PPC of freely behaving rats during selective changes in either the spatial layout of the local environment or in the pattern of locomotor behaviors executed during navigational tasks. The results revealed unequivocally a predominant sensitivity of PPC neurons to locomotor action structure, with subsets of cells even encoding upcoming movements more than 1 s in advance. In light of these and other recent findings in the field, I propose that one of the key contributions of PPC to navigation is the synthesis of goal-directed behavioral sequences, and that the rodent PPC may serve as an apt system to investigate cellular mechanisms for spatial motor planning as traditionally studied in humans and monkeys. PMID:24860475

  4. Widespread Vestibular Activation of the Rodent Cortex

    PubMed Central

    Moya, Javier; Drawitsch, Florian; Brichta, Alan M.

    2015-01-01

    Much of our understanding of the neuronal mechanisms of spatial navigation is derived from chronic recordings in rodents in which head-direction, place, and grid cells have all been described. However, despite the proposed importance of self-reference information to these internal representations of space, their congruence with vestibular signaling remains unclear. Here we have undertaken brain-wide functional mapping using both fMRI and electrophysiological methods to directly determine the spatial extent, strength, and time course of vestibular signaling across the rat forebrain. We find distributed activity throughout thalamic, limbic, and particularly primary sensory cortical areas in addition to known head-direction pathways. We also observe activation of frontal regions, including infralimbic and cingulate cortices, indicating integration of vestibular information throughout functionally diverse cortical regions. These whole-brain activity maps therefore suggest a widespread contribution of vestibular signaling to a self-centered framework for multimodal sensorimotor integration in support of movement planning, execution, spatial navigation, and autonomic responses to gravito-inertial changes. PMID:25878265

  5. Active vibrissal sensing in rodents and marsupials

    PubMed Central

    Mitchinson, Ben; Grant, Robyn A.; Arkley, Kendra; Rankov, Vladan; Perkon, Igor; Prescott, Tony J.

    2011-01-01

    In rats, the long facial whiskers (mystacial macrovibrissae) are repetitively and rapidly swept back and forth during exploration in a behaviour known as whisking. In this paper, we summarize previous evidence from rats, and present new data for rat, mouse and the marsupial grey short-tailed opossum (Monodelphis domestica) showing that whisking in all three species is actively controlled both with respect to movement of the animal's body and relative to environmental structure. Using automatic whisker tracking, and Fourier analysis, we first show that the whisking motion of the mystacial vibrissae, in the horizontal plane, can be approximated as a blend of two sinusoids at the fundamental frequency (mean 8.5, 11.3 and 7.3 Hz in rat, mouse and opossum, respectively) and its second harmonic. The oscillation at the second harmonic is particularly strong in mouse (around 22 Hz) consistent with previous reports of fast whisking in that species. In all three species, we found evidence of asymmetric whisking during head turning and following unilateral object contacts consistent with active control of whisker movement. We propose that the presence of active vibrissal touch in both rodents and marsupials suggests that this behavioural capacity emerged at an early stage in the evolution of therian mammals. PMID:21969685

  6. Mother–Pup Interactions: Rodents and Humans

    PubMed Central

    Lucion, Aldo B.; Bortolini, Maria Cátira

    2014-01-01

    In order to survive after birth, mammalian infants need a caretaker, usually the mother. Several behavioral strategies have evolved to guarantee the transition from a period of intense caregiving to offspring independence. Here, we examine a selection of literature on the genetic, epigenetic, physiological, and behavioral factors relating to development and mother–infant interactions. We intend to show the utility of comparisons between rodent and human models for deepening knowledge regarding this key relationship. Particular attention is paid to the following factors: the distinct developmental stages of the mother–pup relationship as relating to behavior; examples of key genetic components of mammalian mother–infant interactions, specifically those coding for the hormones oxytocin and vasopressin; and the possible functions of gene imprinting in mediating interactions between genetics and environment in the mother–infant relationship. As early mother–infant attachment seems to establish the basic parameters for later social interactions, ongoing investigations in this area are essential. We propose the importance of interdisciplinary collaboration in order to better understand the network of genes, gene regulation, neuropeptide action, physiological processes, and feedback loops essential to understand the complex behaviors of mother–infant interaction. PMID:24616713

  7. Assessing spatial learning and memory in rodents.

    PubMed

    Vorhees, Charles V; Williams, Michael T

    2014-01-01

    Maneuvering safely through the environment is central to survival of almost all species. The ability to do this depends on learning and remembering locations. This capacity is encoded in the brain by two systems: one using cues outside the organism (distal cues), allocentric navigation, and one using self-movement, internal cues and nearby proximal cues, egocentric navigation. Allocentric navigation involves the hippocampus, entorhinal cortex, and surrounding structures; in humans this system encodes allocentric, semantic, and episodic memory. This form of memory is assessed in laboratory animals in many ways, but the dominant form of assessment is the Morris water maze (MWM). Egocentric navigation involves the dorsal striatum and connected structures; in humans this system encodes routes and integrated paths and, when overlearned, becomes procedural memory. In this article, several allocentric assessment methods for rodents are reviewed and compared with the MWM. MWM advantages (little training required, no food deprivation, ease of testing, rapid and reliable learning, insensitivity to differences in body weight and appetite, absence of nonperformers, control methods for proximal cue learning, and performance effects) and disadvantages (concern about stress, perhaps not as sensitive for working memory) are discussed. Evidence-based design improvements and testing methods are reviewed for both rats and mice. Experimental factors that apply generally to spatial navigation and to MWM specifically are considered. It is concluded that, on balance, the MWM has more advantages than disadvantages and compares favorably with other allocentric navigation tasks. PMID:25225309

  8. Rodent renal structure differs among species.

    PubMed

    Ichii, Osamu; Yabuki, Akira; Ojima, Toshimichi; Matsumoto, Mitsuharu; Suzuki, Shusaku

    2006-05-01

    In the present study, we histologically and morphometrically investigated species differences in renal structure using laboratory rodents (mice, gerbils, hamsters, rats, and guinea pigs). Morphometric parameters were as follows, 1) diameter of the cortical renal corpuscles, 2) diameter of the juxtamedullary renal corpuscles, 3) percentage of the renal corpuscles with a cuboidal parietal layer, 4) number of nuclei in proximal convoluted tubules (PCTs) per unit area of cortex, 5) semi-quantitative score of the periodic acid-Schiff (PAS) -positive granules in PCTs, and 6) semi-quantitative score of the PAS-positive granules in proximal straight tubules (PSTs). Significant species differences were detected for each parameter, and particularly severe differences were observed in the PAS-positive granules of PCTs and PSTs. Granular scores varied among species and sexes. Vacuolar structures that did not stain with PAS or hematoxylin-eosin were observed in the renal proximal tubules. The appearance and localization of these vacuolar structures differed remarkably between species and sexes. PMID:16757886

  9. A NEW METHOD TO QUANTIFY CORE TEMPERATURE INSTABILITY IN RODENTS.

    EPA Science Inventory

    Methods to quantify instability of autonomic systems such as temperature regulation should be important in toxicant and drug safety studies. Stability of core temperature (Tc) in laboratory rodents is susceptible to a variety of stimuli. Calculating the temperature differential o...

  10. ASSESSMENT OF HOST RESISTANCE TO INFECTION WITH RODENT MALARIA

    EPA Science Inventory

    Resistance to malaria infection is known to require an intact immune system. his chapter presents an overview of rodent malaria, the host response to infection and methods for assessing infection in rats and mice.

  11. MEASUREMENT OF VENTILATORY FREQUENCY IN UNRESTRAINED RODENTS USING MICROWAVE RADIATION

    EPA Science Inventory

    A novel technique for remote determination of breathing frequency in unrestrained rodents using microwave radiation is described. Single mice were placed inside a rectangular waveguide operating at 2450 MHz. Because mice efficiently absorb radio frequency energy at 2450 MHz, any ...

  12. Diet of a sigmodontine rodent assemblage in a Peruvian montane forest

    PubMed Central

    Sahley, Catherine Teresa; Cervantes, Klauss; Pacheco, Victor; Salas, Edith; Paredes, Diego; Alonso, Alfonso

    2015-01-01

    Knowledge of feeding habits of small rodents is necessary for understanding food webs, trophic structure, and plant–animal interactions in Neotropical forests. Despite several studies that have investigated community structure and feeding behavior of rodents, large gaps remain in our understanding of their guild occupancy. Our objective was to investigate the diets of 7 species of small (< 100g) sympatric sigmodontine rodents in a high (3,500 m) Andean montane rainforest in Peru. We qualitatively and quantitatively assessed diet items in fecal samples from livetrapped rodents from 2009 to 2012. Frequency data for 4 diet categories indicated that all 7 species of rodents contained 4 diet categories in fecal samples: arthropods (88%), remains of leaves and fibers from plants (61%), intact seeds (with or without fruit pulp; 50%), and mycorrhizal spores (45%). Omnivory was found to be a strategy used by all species, although contingency table analysis revealed significant differences among and within species in diet categories. Cluster analysis showed 2 main groupings: that of the Thomasomys spp. plus Calomys sorellus group which included high amounts of intact seeds and plant parts in their fecal samples, and those of the genera Akodon, Microryzomys, Oligoryzomys, which included a greater proportion of arthropods in their fecal samples, but still consumed substantial amounts of fruit and plant parts. Intact seed remains from at least 17 plant species (9 families) were found in fecal samples. We concluded that this assemblage of sigmodontine rodents is omnivorous but that they likely play an important role as frugivores and in seed dispersal in tropical montane forests in Peru. El conocimiento de los hábitos alimenticios de roedores pequeños es necesario para comprender cadenas alimenticias, estructura trófica, e interacciones planta-animal en los bosques neotropicales. A pesar de que numerosos estudios han investigado la estructura de comunidades y el comportamiento de forrajeo en roedores, aún existen grandes vacíos en nuestra comprensión de sus gremios tróficos. Nuestro objetivo fue investigar las dietas de siete especies de pequeños (< 100 g) roedores sigmodontinos simpátricos en un bosque montano andino a 3.500] m en Perú. Cualitativamente y cuantitativamente evaluamos la dieta en muestras fecales de roedores capturados entre el 2009 y el 2012. Datos de frecuencia para cuatro categorías de dieta indicaron que las siete especies de roedores consumieron cuatro categorías de dieta: artrópodos (88%), pedazos de hojas y fibras de plantas (61%), semillas intactas (con o sin pulpa de frutos; 50%), y esporas de micorrizas (45%). Omnivoría fue la estrategia utilizada por todas las especies, aunque el análisis con tablas de contingencia reveló diferencias significativas entre y dentro de especies en categorías de dieta. El análisis de agrupación presentó 2 grupos principales: el grupo Thomasomys spp. y Calomys sorellus, que incluye una gran proporción de semillas intactas, y partes de plantas en las muestras fecales y el grupo que incluye los géneros Akodon, Microryzomys y Oligoryzomys, el cual incluyó una proporción mayor de artrópodos en sus muestras fecales, pero con niveles altos de semillas intactas. Semillas intactas de al menos 17 especies de plantas (9 familias) fueron encontradas en las muestras fecales. Concluimos que este ensamble de roedores sigmodontinos es omnívoro y que probablemente las especies juegan un rol importante como frugívoros y en la dispersión de semillas en los bosques montanos tropicales en el Perú. PMID:26937050

  13. Tracking genome organization in rodents by Zoo-FISH.

    PubMed

    Graphodatsky, Alexander S; Yang, Fengtang; Dobigny, Gauthier; Romanenko, Svetlana A; Biltueva, Larisa S; Perelman, Polina L; Beklemisheva, Violetta R; Alkalaeva, Elena Z; Serdukova, Natalya A; Ferguson-Smith, Malcolm A; Murphy, William J; Robinson, Terence J

    2008-01-01

    The number of rodent species examined by modern comparative genomic approaches, particularly chromosome painting, is limited. The use of human whole-chromosome painting probes to detect regions of homology in the karyotypes of the rodent index species, the mouse and rat, has been hindered by the highly rearranged nature of their genomes. In contrast, recent studies have demonstrated that non-murid rodents display more conserved genomes, underscoring their suitability for comparative genomic and higher-order systematic studies. Here we provide the first comparative chromosome maps between human and representative rodents of three major rodent lineages Castoridae, Pedetidae and Dipodidae. A comprehensive analysis of these data and those published for Sciuridae show (1) that Castoridae, Pedetidae and Dipodidae form a monophyletic group, and (2) that the European beaver Castor fiber (Castoridae) and the birch mouse Sicista betulina (Dipodidae) are sister species to the exclusion of the springhare Pedetes capensis (Pedetidae), thus resolving an enduring trifurcation in rodent higher-level systematics. Our results together with published data on the Sciuridae allow the formulation of a putative rodent ancestral karyotype (2n = 50) that is thought to comprise the following 26 human chromosomal segments and/or segmental associations: HSA1pq, 1q/10p, 2pq, 2q, 3a, 3b/19p, 3c/21, 4b, 5, 6, 7a, 7b/16p, 8p/4a/8p, 8q, 9/11, 10q, 12a/22a, 12b/22b, 13, 14/15, 16q/19q, 17, 18, 20, X and Y. These findings provide insights into the likely composition of the ancestral rodent karyotype and an improved understanding of placental genome evolution. PMID:18266061

  14. Tropical Rainfall Measurement Mission

    NASA Technical Reports Server (NTRS)

    Wilheit, T. T.

    1988-01-01

    It has long been noted that anomalies in the sea surface temperature (SST) in the tropics are strongly correlated with climate in the temperate latitudes on a seasonal time scale. The ability to measure the global SST and the atmospheric pressure/temperature patterns has made great progress. However, rainfall measurement, the putative connection between the two, is poorly accomplished. The Tropical Rainfall Measurement Mission (TRMM) was conceived to fill this gap. The TRMM spacecraft would fly in a low inclination, (about 35 deg), orbit which would concentrate the sampling in the very important tropical latitudes. The precession of such an orbit would enable observations at all times of the day over the span of a month which would permit corrections for the diurnal cycle of precipitation which is quite marked in parts of the tropics. The payload of the TRMM spacecraft is carefully designed to provide accurate measurements of rain. It consists of microwave radiometers, a microwave radar and visible/infrared radiometer. The two types of microwave instruments provide direct measurements of the hydrometeors, each having strengths which compensate for weaknesses of the other. The VIS/IR instrument provides a connection to the long time series of VIS/IR measurements from polar and Geosynchronous spacecraft which are currently the best available source of global rainfall estimates. The TRMM is currently in a phase A (feasibility) study.

  15. Rain Forests: Tropical Treasures.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1989-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Rain Forests: Tropical Treasures." Contents are organized into the following…

  16. People & Tropical Rain Forests.

    ERIC Educational Resources Information Center

    NatureScope, 1989

    1989-01-01

    Discusses ways people who live in rain forests make a living and some of the products that enrich our lives. Provides activities covering forest people, tropical treats, jungle in the pantry, treetop explorers, and three copyable pages to accompany activities. (Author/RT)

  17. Rain Forests: Tropical Treasures.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1989-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Rain Forests: Tropical Treasures." Contents are organized into the following

  18. Ectoparasites of Rodents Captured in Hamedan, Western Iran

    PubMed Central

    Zendehfili, Hamid; Zahirnia, Amir Hossein; Maghsood, Amir Hossein; Khanjani, Mohammad; Fallah, Mohammad

    2015-01-01

    Background: Rodents with a population greater than the entire population of other mammals on earth are the source of economic losses and health conflicts. One of the major health problems with the rodents is their role as reservoir hosts of zoonotic diseases. The aim of this study was to assess the infestation of commensal rodents with ectoparasites in Hamedan City, Western Iran. Methods: The samples were collected by live traps during years 2012–2013. After transferring the samples to the Entomological Laboratory of Hamedan University of Medical Sciences, their ectoparasites were collected and identified. Results: A total of 171 slides were prepared from 105 captured commensal rodents: Mus musculus, Rattus rattus and R. norvegicus comprising three orders namely Mesostigmata: Hypoaspis (Laelaspis) astronomica, Dermanyssius sp, Pachylaelapidae (male). Metastigmata: Rhipicephalus sp and Anoplura: Polyplax spinulosa were recovered in Hamedan City. Seventy (66.6%) rodents were found infested with at least one species of ectoparasites. Conclusion: The results of our study indicate that ectoparasites infestation in commensal rodents of Hamedan city is high and more attention by local health authorities is needed to prevent zoonotic diseases. PMID:26623438

  19. Serologic survey of orthopoxvirus infection among rodents in hungary.

    PubMed

    Oldal, Miklós; Sironen, Tarja; Henttonen, Heikki; Vapalahti, Olli; Madai, Mónika; Horváth, Győző; Dallos, Bianka; Kutas, Anna; Földes, Fanni; Kemenesi, Gábor; Németh, Viktória; Bányai, Krisztián; Jakab, Ferenc

    2015-05-01

    As a result of discontinuing vaccination against smallpox after the late 1970s, different orthopoxviruses (OPVs), such as cowpox virus (CPXV), have become a re-emerging healthcare threat among zoonotic pathogens. In Hungary, data on OPV prevalence among its rodent host species have been absent. Here, rodents belonging to four species, i.e., striped field mouse (Apodemus agrarius), yellow-necked mouse (A. flavicollis), wood mouse (A. sylvaticus) and bank vole (Myodes glareolus), were live trapped at 13 sampling plots on a 149-ha area in the Mecsek Mountains, Hungary, from March to September in 2011 and 2012. Rodent sera were collected and screened for OPV-reactive antibodies with an immunfluorescence assay (IFA). Among the 1587 tested rodents, 286 (18.0%) harbored OPV-specific antibodies. Seroprevalence was the highest for the bank vole (71.4%) and the striped field mouse (66.7%). Due to a masting event in the autumn of 2011 across Central Europe, the abundance of bank voles increased drastically in the 2012 season, raising the overall OPV seroprevalence. We provide the first data on OPV occurrence and seroprevalence in rodents in Hungary. The circulation of OPV in rodents in densely populated areas warrants further studies to elucidate the zoonotic potential of OPV in humans. PMID:25988441

  20. Transmission ecology of rodent-borne diseases: New frontiers.

    PubMed

    Bordes, Frdric; Blasdell, Kim; Morand, Serge

    2015-09-01

    Rodents are recognized reservoir hosts for many human zoonotic pathogens. The current trends resulting from anthropocene defaunation suggest that in the future they, along with other small mammals, are likely to become the dominant mammals in almost all human-modified environments. Recent intricate studies on bat-borne emerging diseases have highlighted that many gaps exist in our understanding of the zoonotic transmission of rodent-borne pathogens. This has emphasized the need for scientists interested in rodent-borne diseases to integrate rodent ecology into their analysis of rodent-borne pathogen transmission in order to identify in more detail the mechanisms of spillover and chains of transmission. Further studies are required to better understand the true impact of rodent abundance and the importance of pathogen sharing and circulation in multi-host- multi-pathogen communities. We also need to explore in more depth the roles of generalist and abundant species as the potential links between pathogen-sharing, co-infections and disease transmission. PMID:26176684

  1. Assessing Tropical Cyclone Damage

    NASA Astrophysics Data System (ADS)

    Done, J.; Czajkowski, J.

    2012-12-01

    Landfalling tropical cyclones impact large coastal and inland areas causing direct damage due to winds, storm-surge flooding, tornadoes, and precipitation; as well as causing substantial indirect damage such as electrical outages and business interruption. The likely climate change impact of increased tropical cyclone intensity, combined with increases in exposure, bring the possibility of increased damage in the future. A considerable amount of research has focused on modeling economic damage due to tropical cyclones, and a series of indices have been developed to assess damages under climate change. We highlight a number of ways this research can be improved through a series of case study analyses. First, historical loss estimates are revisited to properly account for; time, impacted regions, the source of damage by type, and whether the damage was direct/indirect and insured/uninsured. Second, the drivers of loss from both the socio-economic and physical side are examined. A case is made to move beyond the use of maximum wind speed to more stable metrics and the use of other characteristics of the wind field such as direction, degree of gustiness, and duration is explored. A novel approach presented here is the potential to model losses directly as a function of climate variables such as sea surface temperature, greenhouse gases, and aerosols. This work is the first stage in the development of a tropical cyclone loss model to enable projections of losses under scenarios of both socio-economic change (such as population migration or altered policy) and physical change (such as shifts in tropical cyclone activity one from basin to another or within the same basin).

  2. Tropical myeloneuropathies: the hidden endemias.

    PubMed

    Romn, G C; Spencer, P S; Schoenberg, B S

    1985-08-01

    Tropical myeloneuropathies include tropical ataxic neuropathy and tropical spastic paraparesis. These disorders occur in geographic isolates in several developing countries and are associated with malnutrition, cyanide intoxication from cassava consumption, tropical malabsorption (TM), vegetarian diets, and lathyrism. TM-malnutrition was a probable cause of myeloneuropathies among Far East prisoners of war in World War II. Clusters of unknown etiology occur in India, Africa, the Seychelles, several Caribbean islands, Jamaica, and Colombia. Treponemal infection (yaws) could be an etiologic factor in the last two. Tropical myeloneuropathies, a serious health problem, are multifactorial conditions that provide unsurpassed opportunities for international cooperation and neurologic research. PMID:2991814

  3. Expression of ORAI1, a Plasma Membrane Resident Subunit of the CRAC Channel, in Rodent and Non-rodent Species

    PubMed Central

    Guzman, Roberto; Valente, Eliane G.; Pretorius, Jim; Pacheco, Efrain; Qi, Meiying; Bennett, Brian D.; Fong, David H.; Lin, Fen-Fen; Bi, Vivian

    2014-01-01

    We determined the expression of ORAI1 protein in rodent and non-rodent tissues using a monoclonal antibody directed against an extracellular loop of the protein. Previous reports using antibodies directed at the C-terminus of ORAI1 have not detected central nervous system (CNS) expression. Our results demonstrate broad tissue expression that includes the CNS using a unique monoclonal antibody specific to an extracellular loop of ORAI1. In addition, we present in situ hybridization (ISH) results using a probe within the middle of the mouse coding region showing CNS expression of Orai1 RNA. We contrast the patterns of rodent and human tissue expression and conclude that rodents have similar expression of ORAI1 in most tissue types when compared to primates, with an important exception being the male reproductive system, where human-specific expression is observed. PMID:25249026

  4. Expression of ORAII, a plasma membrane resident subunit of the CRAC channel, in rodent and non-rodent species.

    PubMed

    Guzman, Roberto; Valente, Eliane G; Pretorius, Jim; Pacheco, Efrain; Qi, Meiying; Bennett, Brian D; Fong, David H; Lin, Fen-Fen; Bi, Vivian; McBride, Helen J

    2014-12-01

    We determined the expression of ORAI1 protein in rodent and non-rodent tissues using a monoclonal antibody directed against an extracellular loop of the protein. Previous reports using antibodies directed at the C-terminus of ORAI1 have not detected central nervous system (CNS) expression. Our results demonstrate broad tissue expression that includes the CNS using a unique monoclonal antibody specific to an extracellular loop of ORAI1. In addition, we present in situ hybridization (ISH) results using a probe within the middle of the mouse coding region showing CNS expression of Orai1 RNA. We contrast the patterns of rodent and human tissue expression and conclude that rodents have similar expression of ORAI1 in most tissue types when compared to primates, with an important exception being the male reproductive system, where human-specific expression is observed. PMID:25249026

  5. Fibrosis worsens chronic lymphedema in rodent tissues.

    PubMed

    Lynch, Laura L; Mendez, Uziel; Waller, Anna B; Gillette, Amani A; Guillory, Roger J; Goldman, Jeremy

    2015-05-15

    Secondary lymphedema in humans is a common consequence of lymph node dissection (LND) to treat breast cancer. A peculiar characteristic of the disease is that lifelong swelling often precipitously appears several years after the surgical treatment, often due to an inflammatory stimulus. Although the incidence of secondary lymphedema dramatically increases after radiation therapy, the relationship between fibrotic scarring and the eventual appearance of lymphedema remains unclear. To clarify the role of fibrosis in secondary lymphedema initiation, we chemically increased fibrosis in rodent tissues with bleomycin and assessed the ability of the local lymphatic system to prevent lymphedema, either acutely or in a chronic state induced by inflammation. We found that bleomycin injections exacerbated fibrotic matrix deposition in an acute mouse tail lymphedema model (P < 0.005), reduced wound closure (P < 0.005), and impaired the ability of tail lymphatics to regenerate (P < 0.005) and reduce the swelling (P < 0.05). When fibrosis was worsened with bleomycin after axillary LND in the rat foreleg, the ability of the foreleg lymphatic system to reduce the chronic state swelling induced by stimulated inflammation was severely impaired (P < 0.005). Indocyanine green lymphography in axillary LND-recovered rat forelegs revealed a worsened lymphatic drainage due to inflammation and bleomycin pretreatment. Although inflammation reduced the drainage of dextran fluid tracer from control forelegs (P < 0.05), the reduction in fluid drainage was more severe after axillary LND when fibrosis was first increased (P < 0.005). These findings demonstrate that fibrosis reduces the lymphatic capacity to functionally regenerate and prevent the chronic appearance of lymphedema. PMID:25770241

  6. Developmental toxicity of engineered nanomaterials in rodents.

    PubMed

    Ema, Makoto; Gamo, Masashi; Honda, Kazumasa

    2016-05-15

    We summarized significant effects reported in the literature on the developmental toxicity of engineered nanomaterials (ENMs) in rodents. The developmental toxicity of ENMs included not only structural abnormalities, but also death, growth retardation, and behavioral and functional abnormalities. Most studies were performed on mice using an injection route of exposure. Teratogenic effects were indicated when multi-walled carbon nanotubes (MWCNTs), single-walled carbon nanotubes (SWCNTs), and TiO2-nanoparticles were administered to mice during early gestation. Reactive oxygen species levels were increased in placentas and malformed fetuses and their placentas after prenatal exposure to MWCNTs and SWCNTs, respectively. The pre- and postnatal mortalities and growth retardation in offspring increased after prenatal exposure to ENMs. Histopathological and functional abnormalities were also induced in placentas after prenatal exposure to ENMs. Maternal exposure to ENMs induced behavioral alterations, histopathological and biochemical changes in the central nervous system, increased susceptibility to allergy, transplacental genotoxicity, and vascular, immunological, and reproductive effects in offspring. The size- and developmental stage-dependent placental transfer of ENMs was noted after maternal exposure. Silver accumulated in the visceral yolk sac after being injected with Ag-NPs during early gestation. Although currently available data has provided initial information on the potential developmental toxicity of ENMs, that on the developmental toxicity of ENMs is still very limited. Further studies using well-characterized ENMs, state-of the-art study protocols, and appropriate routes of exposure are required in order to clarify these developmental effects and provide information suitable for risk assessments of ENMs. PMID:26721308

  7. Rodent model of direct cranial blast injury.

    PubMed

    Kuehn, Reed; Simard, Philippe F; Driscoll, Ian; Keledjian, Kaspar; Ivanova, Svetlana; Tosun, Cigdem; Williams, Alicia; Bochicchio, Grant; Gerzanich, Volodymyr; Simard, J Marc

    2011-10-01

    Traumatic brain injury resulting from an explosive blast is one of the most serious wounds suffered by warfighters, yet the effects of explosive blast overpressure directly impacting the head are poorly understood. We developed a rodent model of direct cranial blast injury (dcBI), in which a blast overpressure could be delivered exclusively to the head, precluding indirect brain injury via thoracic transmission of the blast wave. We constructed and validated a Cranium Only Blast Injury Apparatus (COBIA) to deliver blast overpressures generated by detonating .22 caliber cartridges of smokeless powder. Blast waveforms generated by COBIA replicated those recorded within armored vehicles penetrated by munitions. Lethal dcBI (LD(50) ∼ 515 kPa) was associated with: (1) apparent brainstem failure, characterized by immediate opisthotonus and apnea leading to cardiac arrest that could not be overcome by cardiopulmonary resuscitation; (2) widespread subarachnoid hemorrhages without cortical contusions or intracerebral or intraventricular hemorrhages; and (3) no pulmonary abnormalities. Sub-lethal dcBI was associated with: (1) apnea lasting up to 15 sec, with transient abnormalities in oxygen saturation; (2) very few delayed deaths; (3) subarachnoid hemorrhages, especially in the path of the blast wave; (4) abnormal immunolabeling for IgG, cleaved caspase-3, and β-amyloid precursor protein (β-APP), and staining for Fluoro-Jade C, all in deep brain regions away from the subarachnoid hemorrhages, but in the path of the blast wave; and (5) abnormalities on the accelerating Rotarod that persisted for the 1 week period of observation. We conclude that exposure of the head alone to severe explosive blast predisposes to significant neurological dysfunction. PMID:21639724

  8. A novel platform device for rodent echocardiography.

    PubMed

    Kutschka, Ingo; Sheikh, Ahmad Y; Sista, Ramachandra; Hendry, Stephen L; Chun, Hyung J; Hoyt, Grant; Kutschka, Werner; Pelletier, Marc P; Quertermous, Tom; Wu, Joseph C; Robbins, Robert C

    2008-01-01

    Acquisition of echocardiographic data from rodents is subject to wide variability due to variations in technique. We hypothesize that a dedicated imaging platform can aid in standardization of technique and improve the quality of images obtained. We constructed a device consisting of a boom-mounted steel platform frame (25 x 35 x 3 cm) on which a transparent polyethylene membrane is mounted. The animal is placed onto the membrane and receives continual inhaled anesthesia via an integrated port. The membrane allows for probe positioning from beneath the animal to obtain standard echo-views in left lateral decubitus or prone positions. The frame can be set at any desired angle ranging from 0 to 360 degrees along either the long or short axis. Adult male Sprague-Dawley rats (n = 5) underwent echocardiography (General Electric, Vivid 7, 14 MHz) using the platform. The device allowed for optimal positioning of animals for a variety of standard echocardiographic measurements. Evaluations among all animals showed minimal variability between two different operators and time points. We tested the feasibility of the device for supporting the assessment of cardiac function in a disease model by evaluating a separate cohort of adult male spontaneously hypertensive rats (n = 5) that underwent left anterior descending coronary artery ligation. Serial echocardiography demonstrated statistically significant decreases of fractional shortening and ejection fraction (p < 0.01) 240 days after surgery. Our novel imaging platform allowed for consistent collection of high-quality echocardiographic data from rats. Future studies will focus on improving this technology to allow for standardized high-throughput echocardiographic analysis in small animal models of disease. PMID:18506056

  9. Partial Rodent Genetic Models for Bipolar Disorder

    PubMed Central

    Chen, Guang; Henter, Ioline D.; Manji, Husseini K.

    2015-01-01

    Bipolar disorder (BPD) is a complex clinical phenomenon. This episodic illness comprises at least four features/components: depression, mania, vulnerability to mood swings in euthymic BPD patients, and spontaneous cyclicity in at least some BPD patients. Currently, there is no rodent genetic model capable of encompassing the whole phenotype of BPD exists; however, recent genetic-behavioral studies have delineated partial models for some components of BPD, namely, depression, mania, and vulnerability or resilience to mood swings. p11 knockout (KO), vesicular monoamine transporter 2 (VMAT2) heterozygous KO, and neural cell adhesion molecule (NCAM) KO mice display anhedonia-like symptoms, and treatment with antidepressants rescues this anhedonia-related phenotype. Mutant CLOCK, glutamate receptor 6 (GluR6) KO, and extracellular signal-regulated kinase 1 (ERK1) KO mice exhibit mania-like behavioral clusters referred to as excessive behavioral excitement; at least some of the exhibited behaviors can be rescued through treatment with mood stabilizers or atypical antipsychotics. Neuronal glucocorticoid receptor (GR) overexpressing, B-cell lymphoma 2 (Bcl-2) heterozygous KO, and Bcl-2-associated athanogene (BAG1) heterozygous KO mice show vulnerability to mood swings. In contrast, neuronal BAG1 overexpressing mice display resilience to mood swings. These mutant mouse strains and the behavioral approaches used to characterize these strains offer an emerging set of research tools for the comprehensive understanding of various components of BPD, and the interrelation of these components at the molecular, cellular, and neuronal circuitry levels. These partial genetic models can also be used as complementary tools to augment other existing behavioral tests and paradigms in drug development for BPD. PMID:25236551

  10. [Edema and the tropics].

    PubMed

    Holzer, B R

    2004-11-01

    People visiting or living in tropical or subtropical regions are exposed to various factors, which can lead to edema. Tourists staying for only a short time in the tropics are exposed to different risks, with other disease patterns, than people living in the tropics or immigrants from tropical regions. The differential diagnosis of edema and swelling is extensive and it can sometimes be difficult to distinguish classical edema with fluid retention in the extravascular interstitial space, from lymphedema or swelling due to other aetiologies. The patients often connect the edema to their stay in the tropics although it may have been pre-existing with no obvious relation to their travels. Already the long trip in the plane can lead to an "economy class syndrome" due to deep venous thrombosis. Contacts with animal or plant toxins, parasites or parasitic larvae can produce peripheral edema. The diagnosis can often only be made by taking a meticulous history, checking for eosinophilia and with the help of serological investigations. Chronic lymphedema or elephantiasis of the limbs is often due to blocked lymph vessels by filarial worms. It has to be distinguished from other forms as e.g. podoconiosis due to blockage by mineral particles in barefoot walking people. The trend to book adventure and trekking holidays at high altitude leads to high altitude peripheral edema or non-freezing cold injuries such as frostbites and trench foot. Edema can be an unwanted side effect of a range of drugs e.g. nifedipine, which is used to prevent and treat high altitude pulmonary edema. Protein malnutrition, (Kwashiorkor), and vitamin B6 deficiency, (Beri-Beri) are very rarely observed in immigrants and almost never in tourists. A very painful swelling of fingers and hands in children and young adults of African origin can be observed during a sickle cell crisis. Many protein loosing nephropathies connected with plant and animal toxins but also bacterial, viral or parasitic agents, can lead to edema. But very often edema in tourists or immigrants from the tropics is not related to their stay abroad. To take an accurate history of the itinerary, eating habits and exposure to water etc. is very important. Knowledge of the precise epidemiology and geographic distribution of diseases are essential. PMID:15605460

  11. The first Late Eocene continental faunal assemblage from tropical North America

    NASA Astrophysics Data System (ADS)

    Jimnez-Hidalgo, Eduardo; Smith, Krister T.; Guerrero-Arenas, Rosalia; Alvarado-Ortega, Jesus

    2015-01-01

    To date, the terrestrial faunal record of the North American late Eocene has been recovered from its subtropical and temperate regions. We report the first late Eocene continental faunal assemblage from tropical North America, in southern Mexico. Fossil specimens were collected from mudstones that crop out in the Municipality of Santiago Yolomcatl, in northwestern Oaxaca. Previously published K-Ar ages of 32.90.9 and 35.71.0Ma in overlain nearby volcanic rocks and biostratigraphy of these new localities suggests a Chadronian mammal age for this new local fauna. The assemblage is composed by two turtle taxa, Rhineura, two caniform taxa, a sciurid, a jimomyid rodent, a geomyine rodent, Gregorymys, Leptochoerus, Perchoerus probus, Merycoidodon, a protoceratid, Poebrotherium, Nanotragulus, Miohippus assinoboiensis, a chalicotherid, a tapiroid, cf. Amynodontopsis, Trigonias and the hymenopteran ichnofossils Celliforma curvata and Fictovichnus sciuttoi. The records of these taxa in northwestern Oaxaca greatly expand southerly their former geographic distribution in North America. The records of the geomorph rodents and Nanotragulus extend their former known biochronological range to the late Eocene. The hymenopteran ichnofossils in the localities suggest the presence of a bare soil after periodic waterlogging, under a sub-humid to sub-arid climate. This new local fauna represents the first glimpse of Eocene vertebrate and invertebrate terrestrial life from tropical North America.

  12. Seasonal Variation of Ozone in the Tropical Lower Stratosphere: Southern Tropics are Different from Northern Tropics

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Waugh, Darryn W.; Wang, Lei,; Oman, Luke D.; Douglass, Anne R.; Newman, Paul A.

    2014-01-01

    We examine the seasonal behavior of ozone by using measurements from various instruments including ozonesondes, Aura Microwave Limb Sounder, and Stratospheric Aerosol and Gas Experiment II. We find that the magnitude of the annual variation in ozone, as a percentage of the mean ozone, exhibits a maximum at or slightly above the tropical tropopause. The maximum is larger in the northern tropics than in the southern tropics, and the annual maximum of ozone in the southern tropics occurs 2 months later than that in the northern tropics, in contrast to usual assumption that the tropics can be treated as a horizontally homogeneous region. The seasonal cycles of ozone and other species in this part of the lower stratosphere result from a combination of the seasonal variation of the Brewer-Dobson circulation and the seasonal variation of tropical and midlatitude mixing. In the Northern Hemisphere, the impacts of upwelling and mixing between the tropics and midlatitudes on ozone are in phase and additive. In the Southern Hemisphere, they are not in phase. We apply a tropical leaky pipe model independently to each hemisphere to examine the relative roles of upwelling and mixing in the northern and southern tropical regions. Reasonable assumptions of the seasonal variation of upwelling and mixing yield a good description of the seasonal magnitude and phase in both the southern and northern tropics. The differences in the tracers and transport between the northern and southern tropical stratospheres suggest that the paradigm of well-mixed tropics needs to be revised to consider latitudinal variations within the tropics.

  13. [Diabetogenic tropical pancreatitis].

    PubMed

    Assan, R; Assan, D; Thiebaut, M F; Laloux, S; Clauser, E; Boukersi, A

    1988-01-01

    The tropical calcifying pancreatitis and/or fibrous pancreatitis are responsible for a number of cases of juvenile insulin-dependent diabetes in the Third World countries. World wide distributed in the tropical areas of Asia, Africa and South America, they can also be observed in Europe, in migrants from these countries. Intensive epidemiological and biochemical studies are currently developed in order to shed light on the many obscure points. Classification of the typical calcifying pancreatitis and the related syndromes is a matter of debate. The pathological basis is calcification of the pancreas and echography of the gland may become a cheap convenient relatively specific tool for epidemiology. The clinical syndrome consists of chronic painful pancreatic episodes since childhood, associated with pancreatic exocrine insufficiency, followed by the onset, during adolescence, of diabetes mellitus, which is most of the times insulin dependent. Patients' history is free of chronic alcoholism, but includes constantly chronic caloric and proteic malnutrition. Although insulin dependent this diabetes in not prone to ketosis, due presumably to carnitine deficiency and relative glucagon deficiency (or suppressibility). Insulin resistance is traditionally noted, the pathophysiology of which is unknown. The mechanism of calcification appearance is also undetermined. Either a deficiency in pancreatic stone protein, or the toxic effect of cyanogen glucosides present in cassava and other tropical foodstuffs, or the malnutrition-related deficiency in sulphur-containing aminoacids may be causal factors. No valid experimental model of the disease is available. PMID:3044866

  14. Tropical fevers: Management guidelines

    PubMed Central

    Singhi, Sunit; Chaudhary, Dhruva; Varghese, George M.; Bhalla, Ashish; Karthi, N.; Kalantri, S.; Peter, J. V.; Mishra, Rajesh; Bhagchandani, Rajesh; Munjal, M.; Chugh, T. D.; Rungta, Narendra

    2014-01-01

    Tropical fevers were defined as infections that are prevalent in, or are unique to tropical and subtropical regions. Some of these occur throughout the year and some especially in rainy and post-rainy season. Concerned about high prevalence and morbidity and mortality caused by these infections, and overlapping clinical presentations, difficulties in arriving at specific diagnoses and need for early empiric treatment, Indian Society of Critical Care Medicine (ISCCM) constituted an expert committee to develop a consensus statement and guidelines for management of these diseases in the emergency and critical care. The committee decided to focus on most common infections on the basis of available epidemiologic data from India and overall experience of the group. These included dengue hemorrhagic fever, rickettsial infections/scrub typhus, malaria (usually falciparum), typhoid, and leptospira bacterial sepsis and common viral infections like influenza. The committee recommends a syndromic approach to diagnosis and treatment of critical tropical infections and has identified five major clinical syndromes: undifferentiated fever, fever with rash / thrombocytopenia, fever with acute respiratory distress syndrome (ARDS), fever with encephalopathy and fever with multi organ dysfunction syndrome. Evidence based algorithms are presented to guide critical care specialists to choose reliable rapid diagnostic modalities and early empiric therapy based on clinical syndromes. PMID:24678147

  15. Tropical ecotoxicology: The state of the environment in the tropics

    SciTech Connect

    Lacher, T.E. Jr.; Goldstein, M.I.

    1995-12-31

    Ecotoxicology has focused almost exclusively on temperate zone countries and ecosystems. Tropical ecosystems, including rain forest, tropical dry forest, savanna, wetlands and freshwater ecosystems, have been neglected. These ecosystems combined might contain as much as 75% of global biodiversity. Tropical ecosystems are under increasing threat of development and alteration. The major causes of habitat degradation in the tropics include population growth and urbanization, agricultural expansion, deforestation, and mining. Some of these activities (in particular agriculture, mining, and the manufacturing and chemical industries) also lead to the release of toxic substances into the environment. Little research in ecotoxicology has been done in tropical environments and techniques and procedures developed for temperate environments are often applied, even though physical and chemical environmental parameters in the tropics can be very different. The regulatory environment also varies from country to country. The authors present an extensive literature review of tropical ecotoxicology, with a focus on Latin America and the Caribbean. Most research has focused on water quality and aquatic toxicology. Virtually no research has been done on the effects of toxic substance on tropical wildlife. They present a protocol for tropical ecotoxicology that addresses the special problems associated with doing ecotoxicological research in the tropics. The authors discuss the issue of adapting temperate zone principles and methods to tropical environments. Finally, they discuss priority areas for immediate research. These include large scale agricultural activities, especially bananas, pineapples, and soybeans and gold mining with the associated heavy use of mercury. The authors also present a prioritization of tropical wildlife that appear to be at highest risk of exposure to toxic substances.

  16. Hypergravity Effects on Rodent Pregnancy and Parturition

    NASA Technical Reports Server (NTRS)

    Ronca, A. E.; Baer, L. A.; Mills, N. A.; Wade, C. E.; Dalton, Bonnie (Technical Monitor)

    2002-01-01

    No mammal has yet undergone birth, or parturition, in the microgravity of space. Previous studies (Ronco & Alberts, 2000) have shown that mid-pregnant rat dams exposed to spaceflight (0-g) and landed 48-72 hrs before term successfully delivered robust, healthy offspring Microgravity-exposed dams exhibited twice the expected numbers of labor contractions whereas length of pregnancy, duration of labor, fetal wastage, number of neonates born and litter gender ratios were identical to controls. In the present study, we report the results of rodent pregnancy and parturition at the opposite end of the gravity spectrum, in hypergravity. Dams exposed to either: 1.0-g, 1.5-g, 1.75-g or 2.0-g from Gestational day (G) 11 and throughout the births of their litters had comparable pregnancy and labor durations, fetal wastage, numbers of neonates born and litter Tender ratios. During parturition, hypergravity-exposed dams exhibited significantly fewer labor contractions as compared to 1.0-g controls. Dams that underwent birth in hypergravity had significantly fewer offspring surviving the immediate postpartum period (P1: 1.0-g, 11.92 +/- 2.84; 1.5-g, 10.88 +/- 2.17; 1.75-g, 9.22 +/-1.99; 2.0-g, 8.83 +/- 3.31). Within 24 hrs postpartum, neonatal survival was further diminished in hypergravity [P2: 100% (1.0-g); 96% (1.5-g); 96% (1.75-g); 73% (2.0-g)] and continued to decline (P10: 100%(1.0-g.); 90%(1.5-g); 87%(1.75-g), 40%(2.0-g)]. Neonatal losses stabilized by P5 for the 1.5-g andl.75-g conditions but continued until P9 for the 2.0-g condition. Together, these findings show that postnatal, but not prenatal, survival is compromised following birth in hypergravity, Maternal and neonatal factors that contribute to peri-parturitional vulnerability to altered gravity environments will be discussed.

  17. Lassa fever or lassa hemorrhagic fever risk to humans from rodent-borne zoonoses.

    PubMed

    El-Bahnasawy, Mamdouh M; Megahed, Laila Abdel-Mawla; Abdalla Saleh, Hala Ahmed; Morsy, Tosson A

    2015-04-01

    Viral hemorrhagic fevers (VHFs) typically manifest as rapidly progressing acute febrile syndromes with profound hemorrhagic manifestations and very high fatality rates. Lassa fever, an acute hemorrhagic fever characterized by fever, muscle aches, sore throat, nausea, vomiting, diarrhea and chest and abdominal pain. Rodents are important reservoirs of rodent-borne zoonosis worldwide. Transmission rodents to humans occur by aerosol spread, either from the genus Mastomys rodents' excreta (multimammate rat) or through the close contact with infected patients (nosocomial infection). Other rodents of the genera Rattus, Mus, Lemniscomys, and Praomys are incriminated rodents hosts. Now one may ask do the rodents' ectoparasites play a role in Lassa virus zoonotic transmission. This paper summarized the update knowledge on LHV; hopping it might be useful to the clinicians, nursing staff, laboratories' personals as well as those concerned zoonoses from rodents and rodent control. PMID:26012219

  18. Global parasite and Rattus rodent invasions: The consequences for rodent-borne diseases.

    PubMed

    Morand, Serge; Bordes, Frédéric; Chen, Hsuan-Wien; Claude, Julien; Cosson, Jean-François; Galan, Maxime; Czirják, Gábor Á; Greenwood, Alex D; Latinne, Alice; Michaux, Johan; Ribas, Alexis

    2015-09-01

    We summarize the current knowledge on parasitism-related invasion processes of the globally invasive Rattus lineages, originating from Asia, and how these invasions have impacted the local epidemiology of rodent-borne diseases. Parasites play an important role in the invasion processes and successes of their hosts through multiple biological mechanisms such as "parasite release," "immunocompetence advantage," "biotic resistance" and "novel weapon." Parasites may also greatly increase the impact of invasions by spillover of parasites and other pathogens, introduced with invasive hosts, into new hosts, potentially leading to novel emerging diseases. Another potential impact is the ability of the invader to amplify local parasites by spillback. In both cases, local fauna and humans may be exposed to new health risks, which may decrease biodiversity and potentially cause increases in human morbidity and mortality. Here we review the current knowledge on these processes and propose some research priorities. PMID:26037785

  19. Public health importance of rodents in South America

    PubMed Central

    Mackenzie, R. B.

    1972-01-01

    Indigenous South American rodents are abundant, varied, and adaptable, and occupy most of the available natural habitats. Knowledge of their taxonomy and biology is generally superficial. Near human habitations the introduced Rattus and Mus are common and their contacts with man are often close. Cities in South America are expanding to keep pace with increases in the human population and hitherto virgin land is being settled or cleared for food production. Thus domestic rodents are brought into contact with indigenous species and the inevitable exchange of parasites may then produce unpredictable threats to human health. The role of both wild and domestic rodents in the transmission of certain infectious diseases, such as plague, sylvatic Venezuelan encephalitis, South American haemorrhagic fevers, murine typhus, and cutaneous leishmaniasis, is well established. The involvement of rodents in some other diseases, such as leptospirosis, American trypanosomiasis, South American hydatid disease, and vesicular stomatitis, is less well understood. In certain other infections, including bartonellosis and the South American spotted fevers, a wild rodent reservoir is inferred but not yet identified. PMID:4539412

  20. Methodological considerations for measuring spontaneous physical activity in rodents.

    PubMed

    Teske, Jennifer A; Perez-Leighton, Claudio E; Billington, Charles J; Kotz, Catherine M

    2014-05-15

    When exploring biological determinants of spontaneous physical activity (SPA), it is critical to consider whether methodological factors differentially affect rodents and the measured SPA. We determined whether acclimation time, sensory stimulation, vendor, or chamber size affected measures in rodents with varying propensity for SPA. We used principal component analysis to determine which SPA components (ambulatory and vertical counts, time in SPA, and distance traveled) best described the variability in SPA measurements. We compared radiotelemetry and infrared photobeams used to measure SPA and exploratory activity. Acclimation time, sensory stimulation, vendor, and chamber size independently influenced SPA, and the effect was moderated by the propensity for SPA. A 24-h acclimation period prior to SPA measurement was sufficient for habituation. Principal component analysis showed that ambulatory and vertical measurements of SPA describe different dimensions of the rodent's SPA behavior. Smaller testing chambers and a sensory attenuation cubicle around the chamber reduced SPA. SPA varies between rodents purchased from different vendors. Radiotelemetry and infrared photobeams differ in their sensitivity to detect phenotypic differences in SPA and exploratory activity. These data highlight methodological considerations in rodent SPA measurement and a need to standardize SPA methodology. PMID:24598463

  1. Rodent Models of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

    PubMed Central

    Imajo, Kento; Yoneda, Masato; Kessoku, Takaomi; Ogawa, Yuji; Maeda, Shin; Sumida, Yoshio; Hyogo, Hideyuki; Eguchi, Yuichiro; Wada, Koichiro; Nakajima, Atsushi

    2013-01-01

    Research in nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), has been limited by the availability of suitable models for this disease. A number of rodent models have been described in which the relevant liver pathology develops in an appropriate metabolic context. These models are promising tools for researchers investigating one of the key issues of NASH: not so much why steatosis occurs, but what causes the transition from simple steatosis to the inflammatory, progressive fibrosing condition of steatohepatitis. The different rodent models can be classified into two large groups. The first includes models in which the disease is acquired after dietary or pharmacological manipulation, and the second, genetically modified models in which liver disease develops spontaneously. To date, no single rodent model has encompassed the full spectrum of human disease progression, but individual models can imitate particular characteristics of human disease. Therefore, it is important that researchers choose the appropriate rodent models. The purpose of the present review is to discuss the metabolic abnormalities present in the currently available rodent models of NAFLD, summarizing the strengths and weaknesses of the established models and the key findings that have furthered our understanding of the diseases pathogenesis. PMID:24192824

  2. Old World Hantaviruses in Rodents in New Orleans, Louisiana

    PubMed Central

    Cross, Robert W.; Waffa, Bradley; Freeman, Ashley; Riegel, Claudia; Moses, Lina M.; Bennett, Andrew; Safronetz, David; Fischer, Elizabeth R.; Feldmann, Heinz; Voss, Thomas G.; Bausch, Daniel G.

    2014-01-01

    Seoul virus, an Old World hantavirus, is maintained in brown rats and causes a mild form of hemorrhagic fever with renal syndrome (HFRS) in humans. We captured rodents in New Orleans, Louisiana and tested them for the presence of Old World hantaviruses by reverse transcription polymerase chain reaction (RT-PCR) with sequencing, cell culture, and electron microscopy; 6 (3.4%) of 178 rodents capturedall brown ratswere positive for a Seoul virus variant previously coined Tchoupitoulas virus, which was noted in rodents in New Orleans in the 1980s. The finding of Tchoupitoulas virus in New Orleans over 25 years since its first discovery suggests stable endemicity in the city. Although the degree to which this virus causes human infection and disease remains unknown, repeated demonstration of Seoul virus in rodent populations, recent cases of laboratory-confirmed HFRS in some US cities, and a possible link with hypertensive renal disease warrant additional investigation in both rodents and humans. PMID:24639295

  3. Observations on the food habits of some African rodents.

    PubMed

    Iwuala, M O; Braide, E I; Maduka, N

    1980-12-01

    Food habits of four common species of African rodents: the giant rat (Cricetomys gambianus), the black house rat (Rattus rattus), the multimammate rat (Mastomys natalensis) and the pygmy mouse (Mus minutoides) were studied on the basis of stomach content analysis, habitat sampling and experimental trials with caged animals. Vegetable items (especially grass, grains and tubers) formed the bulk of the food of all the species. Oil-palm nuts and kernels were also common in the guts of C. gambianus and M. natalensis. Animal food components of all the rodent species comprised mainly insects (especially ants, crickets etc.). Vertebrate flesh and scales were also well represented in the guts of C. gambianus. Domestic and miscellaneous food items were recorded from R. rattus, most of which were trapped in human and animal shelters. Inorganic gut contents, primarily sand grains, were found in sizeable quantities in more than 70% of the rodents examined. Results of experimental feeding trials with caged rodents showed close correlation with those recorded from field samples, especially in terms of food choices and the relative quantities consumed. The ecological and practical implications of these observations are discussed in the light of the importance of the rodents as agricultural and domestic pests. PMID:7323341

  4. Fibroblasts From Long-Lived Rodent Species Exclude Cadmium

    PubMed Central

    Dostál, Lubomír; Kohler, William M.; Penner-Hahn, James E.; Miller, Richard A.

    2015-01-01

    Resistance to the lethal effects of cellular stressors, including the toxic heavy metal cadmium (Cd), is characteristic of fibroblast cell lines derived from long-lived bird and rodent species, as well as cell lines from several varieties of long-lived mutant mice. To explore the mechanism of resistance to Cd, we used inductively coupled plasma mass spectroscopy to measure the rate of Cd uptake into primary fibroblasts of 15 rodent species. These data indicate that fibroblasts from long-lived rodent species have slower rates of Cd uptake from the extracellular medium than those from short-lived species. In addition, fibroblasts from short-lived species export more zinc after exposure to extracellular Cd than cells from long-lived species. Lastly, fibroblasts from long-lived rodent species have lower baseline concentrations of two redox-active metals, iron and copper. Our results suggest that evolution of longevity among rodents required adjustment of cellular properties to alter metal homeostasis and to reduce the toxic effects of heavy metals that accumulate over the course of a longer life span. PMID:24522391

  5. Antenatal maternal hypoxia: criterion for fetal growth restriction in rodents

    PubMed Central

    Jang, Eeun Amy; Longo, Lawrence D.; Goyal, Ravi

    2015-01-01

    Rodents are a useful model for life science research. Accumulating evidence suggests that the offspring of mice and rats suffer from similar disorders as humans when exposed to hypoxia during pregnancy. Importantly, with antenatal hypoxic exposure, human neonates demonstrate low birth weight or growth restriction. Similarly, with antenatal hypoxic exposure rodents also demonstrate the fetal growth restriction (FGR). Surprisingly, there is no consensus on the minimum duration or degree of hypoxic exposure required to cause FGR in rodents. Thus, we have reviewed the available literature in an attempt to answer these questions. Based on studies in rats, birth weight reduction of 31% corresponded to 10th percentile reduction in birth weight curve. With the similar criterion (10th percentile), in mice 3 days or more and in rats 7 days or more of 14% or lower hypoxia administration was required to produce statistically significant FGR. PMID:26106333

  6. Anatomy and Histology of Rodent and Human Major Salivary Glands

    PubMed Central

    Amano, Osamu; Mizobe, Kenichi; Bando, Yasuhiko; Sakiyama, Koji

    2012-01-01

    Major salivary glands of both humans and rodents consist of three pairs of macroscopic glands: parotid, submandibular, and sublingual. These glands secrete serous, mucous or mixed saliva via the proper main excretory ducts connecting the glandular bodies with the oral cavity. A series of discoveries about the salivary ducts in the 17th century by Niels Stensen (16381686), Thomas Wharton (16141673), and Caspar Bartholin (16551738) established the concept of exocrine secretion as well as salivary glands. Recent investigations have revealed the endocrine functions of parotin and a variety of cell growth factors produced by salivary glands. The present review aims to describe macroscopic findings on the major salivary glands of rodents and the microscopic differences between those of humans and rodents, which review should be of interest to those researchers studying salivary glands. PMID:23209333

  7. Detection of porcine circovirus in rodents - short communication.

    PubMed

    Lorincz, Mrta; Csgola, Attila; Biksi, Imre; Szeredi, Levente; Dn, Adm; Tuboly, Tams

    2010-06-01

    Porcine circoviruses (PCV) are present worldwide, infecting domestic pigs and wild boars alike. Studies under laboratory conditions indicated that PCV can be taken up by mice and the virus can replicate in these animals. The possible role of rodents in maintaining and transmitting PCV2 infection in the field has not been investigated yet. The present study reports the detection of PCV2, the pathogenic form of the virus, in mice and rats. A number of rodents, such as mice, rats and voles, were collected at PCV2-infected farms and also outside pig herds and tested for the presence of the virus by polymerase chain reaction (PCR). The results indicated that PCV2 can be present both in mice and rats (65.0% and 23.8% positivity, respectively) on the infected premises, but those rodents that were collected outside pig farms remained negative for PCV2. PMID:20460225

  8. Can shrub cover increase predation risk for a desert rodent?

    USGS Publications Warehouse

    Schooley, R.L.; Sharpe, Peter B.

    1996-01-01

    Previous research indicates that predation risk may influence activity patterns, habitat partitioning, and community structure of nocturnal desert rodents. Shrub microhabitat is typically considered safer than open microhabitat for these small mammals. We investigated predation risk for Townsend's ground squirrels (Spermophilus townsendii), which are diurnal desert rodents that detect predators visually and use burrows for refuge. Our results suggested that shrub cover may increase risk for these squirrels by decreasing their ability to escape from predators. Our field experiment indicated that running speeds of juvenile squirrels were lower in shrub (Ceratoides lanata) habitat than in open areas. Shrub cover was also associated with shorter predator-detection distances (mammalian and avian) and fewer refuges (burrow entrances per hectare) than in open areas in one year but not in another. Our study demonstrated that the visual and locomotive obstruction of vegetative cover may increase predation risk for diurnal desert rodents and that elements of habitat-dependent risk may be temporally dynamic.

  9. Unexpected primitive rodents in the Quaternary of Argentina

    NASA Astrophysics Data System (ADS)

    Vucetich, Mara G.; Vieytes, Emma C.; Verzi, Diego H.; Noriega, Jorge I.; Tonni, Eduardo P.

    2005-10-01

    This article describes the first fossils recorded in the Hernandarias Formation (Pleistocene) in Entre Ros province (eastern Argentina). They are represented by three teeth assigned to the caviomorph rodents (Rodentia, Mammalia) Aenigmys diamantensis gen. et sp. nov. and Eumysops. To establish the phylogenetic affinities of the two most enigmatic teeth, their enamel microstructure was studied. Aenigmys diamantensis is considered the most primitive taxon of a clade formed by Dinomyidae-Neoepiblemidae-Heptaxodontidae. Evidence of the close relationships among these families also is presented herein. The new fossils reinforce previous hypotheses about the survival of primitive Brazilian taxa after their extinction in the Pampas and Patagonia of southern South America. They also show that the diversity of caviomorph rodents during the Quaternary was greater than supposed and that an important Quaternary extinction, not previously detected, affected several lineages. With the available evidence, it is not possible to determine if these rodents indicate a warm pulse or a particular biogeographic situation in Entre Ros.

  10. Rodents for comparative aging studies: from mice to beavers

    PubMed Central

    Bozzella, Michael J.; Seluanov, Andrei

    2008-01-01

    After humans, mice are the best-studied mammalian species in terms of their biology and genetics. Gerontological research has used mice and rats extensively to generate short- and long-lived mutants, study caloric restriction and more. Mice and rats are valuable model organisms thanks to their small size, short lifespans and fast reproduction. However, when the goal is to further extend the already long human lifespan, studying fast aging species may not provide all the answers. Remarkably, in addition to the fast-aging species, the order Rodentia contains multiple long-lived species with lifespans exceeding 20years (naked mole-rat, beavers, porcupines, and some squirrels). This diversity opens great opportunities for comparative aging studies. Here we discuss the evolution of lifespan in rodents, review the biology of slow-aging rodents, and show an example of how the use of a comparative approach revealed that telomerase activity coevolved with body mass in rodents. PMID:19424861

  11. Multiple Infections of Rodents with Zoonotic Pathogens in Austria

    PubMed Central

    Schmidt, Sabrina; Essbauer, Sandra S.; Mayer-Scholl, Anne; Poppert, Sven; Schmidt-Chanasit, Jonas; Klempa, Boris; Henning, Klaus; Schares, Gereon; Groschup, Martin H.; Spitzenberger, Friederike; Richter, Dania; Heckel, Gerald

    2014-01-01

    Abstract Rodents are important reservoirs for a large number of zoonotic pathogens. We examined the occurrence of 11 viral, bacterial, and parasitic agents in rodent populations in Austria, including three different hantaviruses, lymphocytic choriomeningitis virus, orthopox virus, Leptospira spp., Borrelia spp., Rickettsia spp., Bartonella spp., Coxiella burnetii, and Toxoplasma gondii. In 2008, 110 rodents of four species (40 Clethrionomys glareolus, 29 Apodemus flavicollis, 26 Apodemus sylvaticus, and 15 Microtus arvalis) were trapped at two rural sites in Lower Austria. Chest cavity fluid and samples of lung, spleen, kidney, liver, brain, and ear pinna skin were collected. We screened selected tissue samples for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, Leptospira, Borrelia, Rickettsia, Bartonella spp., C. burnetii, and T. gondii by RT-PCR/PCR and detected nucleic acids of Tula hantavirus, Leptospira spp., Borrelia afzelii, Rickettsia spp., and different Bartonella species. Serological investigations were performed for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, and Rickettsia spp. Here, Dobrava-Belgrade hantavirus-, Tula hantavirus-, lymphocytic choriomeningitis virus-, orthopox virus-, and rickettsia-specific antibodies were demonstrated. Puumala hantavirus, C. burnetii, and T. gondii were neither detected by RT-PCR/PCR nor by serological methods. In addition, multiple infections with up to three pathogens were shown in nine animals of three rodent species from different trapping sites. In conclusion, these results show that rodents in Austria may host multiple zoonotic pathogens. Our observation raises important questions regarding the interactions of different pathogens in the host, the countermeasures of the host's immune system, the impact of the host–pathogen interaction on the fitness of the host, and the spread of infectious agents among wild rodents and from those to other animals or humans. PMID:24915446

  12. Are Synonymous Sites in Primates and Rodents Functionally Constrained?

    PubMed

    Price, Nicholas; Graur, Dan

    2016-01-01

    It has been claimed that synonymous sites in mammals are under selective constraint. Furthermore, in many studies the selective constraint at such sites in primates was claimed to be more stringent than that in rodents. Given the larger effective population sizes in rodents than in primates, the theoretical expectation is that selection in rodents would be more effective than that in primates. To resolve this contradiction between expectations and observations, we used processed pseudogenes as a model for strict neutral evolution, and estimated selective constraint on synonymous sites using the rate of substitution at pseudosynonymous and pseudononsynonymous sites in pseudogenes as the neutral expectation. After controlling for the effects of GC content, our results were similar to those from previous studies, i.e., synonymous sites in primates exhibited evidence for higher selective constraint that those in rodents. Specifically, our results indicated that in primates up to 24% of synonymous sites could be under purifying selection, while in rodents synonymous sites evolved neutrally. To further control for shifts in GC content, we estimated selective constraint at fourfold degenerate sites using a maximum parsimony approach. This allowed us to estimate selective constraint using mutational patterns that cause a shift in GC content (GT?TG, CT?TC, GA?AG, and CA?AC) and ones that do not (AT?TA and CG?GC). Using this approach, we found that synonymous sites evolve neutrally in both primates and rodents. Apparent deviations from neutrality were caused by a higher rate of C?A and C?T mutations in pseudogenes. Such differences are most likely caused by the shift in GC content experienced by pseudogenes. We conclude that previous estimates according to which 20-40% of synonymous sites in primates were under selective constraint were most likely artifacts of the biased pattern of mutation. PMID:26563252

  13. Excitation-inhibition discoordination in rodent models of mental disorders.

    PubMed

    Fenton, André A

    2015-06-15

    Animal models of mental illness provide a foundation for evaluating hypotheses for the mechanistic causes of mental illness. Neurophysiological investigations of neural network activity in rodent models of mental dysfunction are reviewed from the conceptual framework of the discoordination hypothesis, which asserts that failures of neural coordination cause cognitive deficits in the judicious processing and use of information. Abnormal dynamic coordination of excitatory and inhibitory neural discharge in pharmacologic and genetic rodent models supports the discoordination hypothesis. These observations suggest excitation-inhibition discoordination and aberrant neural circuit dynamics as causes of cognitive impairment, as well as therapeutic targets for cognition-promoting treatments. PMID:25895430

  14. Stress, social behavior, and resilience: Insights from rodents

    PubMed Central

    Beery, Annaliese K.; Kaufer, Daniela

    2014-01-01

    The neurobiology of stress and the neurobiology of social behavior are deeply intertwined. The social environment interacts with stress on almost every front: social interactions can be potent stressors; they can buffer the response to an external stressor; and social behavior often changes in response to stressful life experience. This review explores mechanistic and behavioral links between stress, anxiety, resilience, and social behavior in rodents, with particular attention to different social contexts. We consider variation between several different rodent species and make connections to research on humans and non-human primates. PMID:25562050

  15. Maintaining and Monitoring the Defined Microbiota Status of Gnotobiotic Rodents.

    PubMed

    Nicklas, Werner; Keubler, Lydia; Bleich, Andr

    2015-01-01

    Gnotobiotic (germfree, defined colonized) rodents have become powerful tools to advance our understanding of the host-microbiome relationship. However, the maintenance and ultimately the monitoring of gnotobiotic rodents is a critical, labor-intensive, and costly process (e.g., sterility, not absence of specific pathogens, must be demonstrated in germfree animals). Here, we provide information on the housing and maintenance of gnotobiotic animals, elucidate prophylactic measurements to avoid contamination, and make specific recommendations for sampling procedures, sampling frequencies, and test methods. PMID:26323633

  16. Tropical Whitefly IPM Project.

    PubMed

    Morales, Francisco J

    2007-01-01

    The Tropical Whitefly IPM Project (TWFP) is an initiative of the Systemwide IPM Programme of the Consultative Group on International Agricultural Research (CGIAR), financed by the Department for International Development (DFID) of the United Kingdom, the Danish International Development Agency (DANIDA), the United States Department of Agriculture (USDA) and Agency for International Development (USAID), the Australian Centre for International Agricultural Research (ACIAR), and the New Zealand Agency for International Development (NZAID), to manage whitefly pests and whitefly-transmitted viruses in the Tropics. Participating CGIAR and other international centers include the Centre for International Tropical Agriculture (CIAT); the International Institute of Tropical Agriculture (IITA); The International Potato Centre (CIP); the Asian Vegetable Research and Development Centre (AVRDC); and the International Centre of Insect Physiology and Ecology (ICIPE), in close collaboration with the National Resources Institute (NRI-UK); national agricultural research institutions; agricultural universities; and advanced agricultural research laboratories in Africa, Asia, Europe, the Pacific Region, and the Americas. The TWFP was launched in 1996 as five separate but closely linked subprojects targeting: (1) Bemisia tabaci as a vector of viruses affecting cassava and sweet potato in sub-Saharan Africa (IITA, NRI, CIP, CIAT); (2) B. tabaci as a vector of viruses in mixed cropping systems of Mexico, Central America, and the Caribbean (CIAT); (3) B. tabaci as a vector of viruses in mixed cropping systems of eastern and southern Africa (ICIPE, AVRDC); (4) B. tabaci as a vector of viruses in mixed cropping systems of Southeast Asia (AVRDC); (5) Trialeurodes vaporariorum as a pest in mixed cropping systems of the Andean highlands (CIAT); and (6) whiteflies as pests of cassava in South America (CIAT). Diagnostic surveys conducted in Phase I (1997-2000) clearly showed that the two main whitefly pests in the Tropics are B. tabaci and, in the highlands, T. vaporariorum. Other whitefly species investigated by the TWFP included B. afer and Aleurotrachelus socialis. B. tabaci is the main vector of plant viruses inducing African cassava mosaic disease, sweet potato virus disease, bean golden mosaic disease, and many other diseases of horticultural crops, mainly tomato, hot and sweet peppers, squash, melon, and several other cucurbits. Genetic resistance was identified as the most important component of an IPM programme, followed by phytosanitary, cultural and legal measures. The two most important factors contributing to whitefly/virus epidemics were shown to be pesticide abuse and the use of virus-infected planting materials. Biological control is only effective in cropping systems with minimal or rational use of insecticides, and should be considered only as a complementary IPM strategy. Farmer education and technical assistance are considered the most critical steps toward the implementation of sustainable and economically viable IPM strategies in tropical countries affected by whitefly pests and whitefly-transmitted viruses. PMID:17222696

  17. Cloudsat tropical cyclone database

    NASA Astrophysics Data System (ADS)

    Tourville, Natalie D.

    CloudSat (CS), the first 94 GHz spaceborne cloud profiling radar (CPR), launched in 2006 to study the vertical distribution of clouds. Not only are CS observations revealing inner vertical cloud details of water and ice globally but CS overpasses of tropical cyclones (TC's) are providing a new and exciting opportunity to study the vertical structure of these storm systems. CS TC observations are providing first time vertical views of TC's and demonstrate a unique way to observe TC structure remotely from space. Since December 2009, CS has intersected every globally named TC (within 1000 km of storm center) for a total of 5,278 unique overpasses of tropical systems (disturbance, tropical depression, tropical storm and hurricane/typhoon/cyclone (HTC)). In conjunction with the Naval Research Laboratory (NRL), each CS TC overpass is processed into a data file containing observational data from the afternoon constellation of satellites (A-TRAIN), Navy's Operational Global Atmospheric Prediction System Model (NOGAPS), European Center for Medium range Weather Forecasting (ECMWF) model and best track storm data. This study will describe the components and statistics of the CS TC database, present case studies of CS TC overpasses with complementary A-TRAIN observations and compare average reflectivity stratifications of TC's across different atmospheric regimes (wind shear, SST, latitude, maximum wind speed and basin). Average reflectivity stratifications reveal that characteristics in each basin vary from year to year and are dependent upon eye overpasses of HTC strength storms and ENSO phase. West Pacific (WPAC) basin storms are generally larger in size (horizontally and vertically) and have greater values of reflectivity at a predefined height than all other basins. Storm structure at higher latitudes expands horizontally. Higher vertical wind shear (≥ 9.5 m/s) reduces cloud top height (CTH) and the intensity of precipitation cores, especially in HTC strength storms. Average zero and ten dBZ height thresholds confirm WPAC storms loft precipitation sized particles higher into the atmosphere than in other basins. Two CS eye overpasses (32 hours apart) of a weakening Typhoon Nida in 2009 reveal the collapse of precipitation cores, warm core anomaly and upper tropospheric ice water content (IWC) under steady moderate shear conditions.

  18. European Cloth and Tropical Skin:

    PubMed Central

    Johnson, Ryan

    2009-01-01

    As Britains imperial and colonial ambitions intensified toward the end of the nineteenth century, the preservation of white European health in tropical climates became an increasingly important concern. Since at least the seventeenth century, the tropics had been seen as spaces holding vast potential wealth but also death and disease. To combat these deadly but desirable landscapes, the British built a considerable commodity culture around the preservation of white European health, and for many, tropical clothing was one of the most important and essential items in their kits. This article investigates the composition and use of such clothing in relation to British ideas of health and hygiene in tropical climates. First, it considers debates that ensued over the best materialwool, cotton, linen, silk, or a combination of these materialsand the role of black skin and local practice in the development of tropical clothing. Second, it demonstrates the importance of location in any discussion of tropical medicine and hygiene, and the tension and ambiguity that still surrounded British ideas of health and hygiene in the tropical colonies. Third, it argues that tropical clothing was important in the maintenance of climatic etiologies despite advances in parasitology and sanitary science. Finally, it considers the relationship of tropical clothing to the formation of a unique colonial identity. To British men and women embarking for any number of tropical destinations, proper clothing was not a banal and mundane component of their outfitting. For many, the clothing signified a departure from the safe and civil climes of Britain for adventure in the expanding tropical empire. PMID:19801795

  19. Seven Guideposts for Tropical Rain Forest Education.

    ERIC Educational Resources Information Center

    Rillero, Peter

    1999-01-01

    Identifies seven guideposts for tropical rain forest education. Aids teachers in finding structure and creating educational experiences that promote more complete understanding of tropical rain forests. (CCM)

  20. Combating tropical deforestation in Haiti

    SciTech Connect

    Pellek, R.

    1990-09-01

    This article outlines the findings of Tropical Forestry Action Plan (TFAP), which was part of an international initiative on tropical deforestation. Ten specific recommendations are addressed. Haiti has lost more than 97% of its forestland, so emphasis should be placed on replenishing the forest cover.

  1. Tropical Soda Apple (Solanum viarum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropical soda apple (Solanum viarum Dunal), a perennial shrub, is a Federal Noxious Weed that continues to spread at an alarming rate in the southeastern United States. Information is provided on the impact of tropical soda apple on agricultural and natural areas, federal regulations for restricted...

  2. Conservation of tropical plant species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book is designed to provide a review of the methods and current status of conservation of many tropical plant species. Future perspectives of conservation of tropical species will also be discussed. The section on methods covers the range of conservation techniques, in situ, seed banking, in vi...

  3. Botany, Chemistry, and Tropical Development.

    ERIC Educational Resources Information Center

    Headrick, Daniel R.

    1996-01-01

    Examines the role played by botany and chemistry in the development, exploitation, and later deterioration of tropical economies. Although near equals in 19th-century international trade, the development of synthetics by European scientists in the early 20th century crippled the tropical economies. Research, innovation, and investment protected

  4. Tropical Rainforest Education. ERIC Digest.

    ERIC Educational Resources Information Center

    Rillero, Peter

    This digest provides four guideposts for tropical rainforest education: (1) structure; (2) location and climate; (3) importance; and (4) conservation of resources. Research is cited and background information provided about the layers of life and the adaptations of life within the tropical rain forest. Aspects of life within and near rain forests…

  5. Rodent community landscape ecology in grassland-shrubland ecotones and gradients in the Chihuahuan Desert

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is believed that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. It has been reported, however, that rodent population responses to spatial variati...

  6. LANDSCAPE VARIATION IN DESERT RODENT COMMUNITY RESPONSE TO GRASS-SHRUBLAND ECOTONES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Desert rodents exert strong effects on soil, vegetation, and other animals. It has been reported that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. ...

  7. Tuberculosis in the tropics.

    PubMed

    Maartens, Gary; Beyers, Nulda

    2002-06-01

    Tropical countries bear the brunt of the global TB burden. Young children are at high risk and suffer the most severe forms of TB; adults with pulmonary cavities are the main sources of transmission. The incidence in sub-Saharan Africa is increasing as a consequence of the HIV pandemic. Smear-negative TB, which is common in children and patients who have HIV infection, is becoming a major problem in resource-poor settings where access to mycobacterial culture and histopathology is limited. Clinical case definitions are being developed to address this problem. Short courses of rifampin-based therapy are not universally available, but access is increasing. DOTS is the main strategy that the WHO is promoting to improve TB control. This is particularly important for sputum smear-positive patients. Unfortunately, the DOTS targets set by the WHO have not yet been met. Innovative, low-cost ways of supervising therapy have been developed using family members or lay supervisors. Preventive therapy in tropical countries is limited to high-risk cases (young children and HIV-infected patients who are tuberculin skin test-positive). An improved TB vaccine would dramatically improve TB control. PMID:12092029

  8. Tropical pulmonary eosinophilia.

    PubMed

    Ong, R K; Doyle, R L

    1998-06-01

    Tropical pulmonary eosinophilia (TPE) usually affects people living in the tropics, especially those in Southeast Asia, India, and certain parts of China and Africa. However, owing to the rising frequency of world-wide travel and the migration between continents, this disease is increasingly seen in the West, where the diagnosis can be easily missed since it is rarely encountered and can mimic many other conditions. Cases of TPE have typically been reported to masquerade as acute or refractory bronchial asthma. TPE results from a hypersensitivity reaction to lymphatic filarial parasites found in endemic regions. There is evidence that it is more likely to occur in nonimmune individuals, ie, visitors to endemic regions, than in individuals of endemic populations who have developed immunity to filarial infections. Clinical features include paroxysmal cough, wheezing and dyspnea, and systemic manifestations such as fever and weight loss. A history of residence in a filarial endemic region and a finding of peripheral eosinophilia >3,000/mm3 should initiate a consideration of this disease. Other criteria for the diagnosis of TPE include absence of microfilariae in the blood, high titers of antifilarial antibodies, raised serum total IgE >1,000 U/mL, and a favorable response to the antifilarial, diethylcarbamazine, which is the recommended treatment. This disease, if left untreated or treated late, may lead to long-term sequelae of pulmonary fibrosis or chronic bronchitis with chronic respiratory failure. Herein lies the importance of early diagnosis and treatment of TPE. PMID:9631810

  9. [Tropical medicine consultation].

    PubMed

    Valerio, L; de Balanz, X

    2006-01-01

    Tropical medicine consultations are fully justified in settings with the latest modern technology, where specific complementary tests are available and there are professionals with experience in tropical questions. That is to say, in tertiary hospitals. If such consultations took place in secondary hospitals or in primary care, they could be considered inefficient or unjustifiable from the point of view of the volume of patients attended to. However, there is a care deficit with respect to preventive activities concerning travellers or immigrants who have recently arrived from countries with a low income and where there is a high prevalence of imported diseases that are less recognised in our normal health milieu. Thus, international health units, which combine preventive and curative activities in a framework of public health provision and in a functional situation between the hospital level and that of primary care, offer a more efficient and suitable profile for the characteristics of the Spanish population. Their implementation depends on policy makers, the offer of a realistic portfolio of services, the existence of quality control monitoring and the possibility of managing information through a computer network. PMID:16721420

  10. Tropical Cyclone Information System

    NASA Technical Reports Server (NTRS)

    Li, P. Peggy; Knosp, Brian W.; Vu, Quoc A.; Yi, Chao; Hristova-Veleva, Svetla M.

    2009-01-01

    The JPL Tropical Cyclone Infor ma tion System (TCIS) is a Web portal (http://tropicalcyclone.jpl.nasa.gov) that provides researchers with an extensive set of observed hurricane parameters together with large-scale and convection resolving model outputs. It provides a comprehensive set of high-resolution satellite (see figure), airborne, and in-situ observations in both image and data formats. Large-scale datasets depict the surrounding environmental parameters such as SST (Sea Surface Temperature) and aerosol loading. Model outputs and analysis tools are provided to evaluate model performance and compare observations from different platforms. The system pertains to the thermodynamic and microphysical structure of the storm, the air-sea interaction processes, and the larger-scale environment as depicted by ocean heat content and the aerosol loading of the environment. Currently, the TCIS is populated with satellite observations of all tropical cyclones observed globally during 2005. There is a plan to extend the database both forward in time till present as well as backward to 1998. The portal is powered by a MySQL database and an Apache/Tomcat Web server on a Linux system. The interactive graphic user interface is provided by Google Map.

  11. PERFLUOROOCTANE SULFONATE (PFOS) DISRUPTS THE THYROID STATUS IN LABORATORY RODENTS

    EPA Science Inventory

    PERFLUOROOCTANE SULFONATE (PFOS) DISRUPTS THE THYROID STATUS IN LABORATORY RODENTS. C. Lau, J.R. Thibodeaux, R.G. Hanson, B.E. Gray and J.M. Rogers. Reprod. Tox. Div. NHEERL, US EPA, Research Triangle Park, NC.

    PFOS is an environmental contaminant ubiquitously found in h...

  12. Astronaut Norman Thagard changes tray in RAHF for rodents

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Astronaut Norman Thagard changes a tray in the research animal holding facility (RAHF) for rodents at the Ames double rack facility aboard the Spacelab 3 science module in the cargo bay of the shuttle Challenger. Lending a hand is payload specialist Lodewijk van den Berg. Both men are wearing protective clothing and surgical masks for this procedure.

  13. Comparative Metabolism of Furan in Rodent and Human Cryopreserved Hepatocytes

    PubMed Central

    Gates, Leah A.; Phillips, Martin B.; Matter, Brock A.

    2014-01-01

    Furan is a liver toxicant and carcinogen in rodents. Although humans are most likely exposed to furan through a variety of sources, the effect of furan exposure on human health is still unknown. In rodents, furan requires metabolism to exert its toxic effects. The initial product of the cytochrome P450 2E1-catalyzed oxidation is a reactive ?,?-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). BDA is toxic and mutagenic and consequently is considered responsible for the toxic effects of furan. The urinary metabolites of furan in rats are derived from the reaction of BDA with cellular nucleophiles, and precursors to these metabolites are detected in furan-exposed hepatocytes. Many of these precursors are 2-(S-glutathionyl)butanedial-amine cross-links in which the amines are amino acids and polyamines. Because these metabolites are derived from the reaction of BDA with cellular nucleophiles, their levels are a measure of the internal dose of this reactive metabolite. To compare the ability of human hepatocytes to convert furan to the same metabolites as rodent hepatocytes, furan was incubated with cryopreserved human and rodent hepatocytes. A semiquantitative liquid chromatography with tandem mass spectrometry assay was developed for a number of the previously characterized furan metabolites. Qualitative and semiquantitative analysis of the metabolites demonstrated that furan is metabolized in a similar manner in all three species. These results indicate that humans may be susceptible to the toxic effects of furan. PMID:24751574

  14. DESERT RODENTS REDUCE SEEDLING RECRUITMENT OF SALSOLA PAULSENII

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heteromyid rodents in the deserts of North America have been shown to harvest large quantities of seeds of both native and introduced plants from soil seedbanks, but rarely has the impact of this seed removal been demonstrated experimentally. I used a series of fenced plots (some of which excluded ...

  15. Leptospira spp. in Rodents and Shrews in Germany

    PubMed Central

    Mayer-Scholl, Anne; Hammerl, Jens Andre; Schmidt, Sabrina; Ulrich, Rainer G.; Pfeffer, Martin; Woll, Dietlinde; Scholz, Holger C.; Thomas, Astrid; Nöckler, Karsten

    2014-01-01

    Leptospirosis is an acute, febrile disease occurring in humans and animals worldwide. Leptospira spp. are usually transmitted through direct or indirect contact with the urine of infected reservoir animals. Among wildlife species, rodents act as the most important reservoir for both human and animal infection. To gain a better understanding of the occurrence and distribution of pathogenic leptospires in rodent and shrew populations in Germany, kidney specimens of 2973 animals from 11 of the 16 federal states were examined by PCR. Rodent species captured included five murine species (family Muridae), six vole species (family Cricetidae) and six shrew species (family Soricidae). The most abundantly trapped animals were representatives of the rodent species Apodemus flavicollis, Clethrionomys glareolus and Microtus agrestis. Leptospiral DNA was amplified in 10% of all animals originating from eight of the 11 federal states. The highest carrier rate was found in Microtus spp. (13%), followed by Apodemus spp. (11%) and Clethrionomys spp. (6%). The most common Leptospira genomospecies determined by duplex PCR was L. kirschneri, followed by L. interrogans and L. borgpetersenii; all identified by single locus sequence typing (SLST). Representatives of the shrew species were also carriers of Leptospira spp. In 20% of Crocidura spp. and 6% of the Sorex spp. leptospiral DNA was detected. Here, only the pathogenic genomospecies L. kirschneri was identified. PMID:25062275

  16. Lassa Serology in Natural Populations of Rodents and Horizontal Transmission

    PubMed Central

    Becker-Ziaja, Beate; Koivogui, Lamine; Gnther, Stephan

    2014-01-01

    Abstract Lassa virus causes hemorrhagic fever in West Africa. Previously, we demonstrated by PCR screening that only the multimammate mouse, Mastomys natalensis, hosts Lassa virus in Guinea. In the present study, we used the same specimen collection from 17 villages in Coastal, Upper, and Forest Guinea to investigate the Lassa virus serology in the rodent population. The aim was to determine the dynamics of antibody development in M. natalensis and to detect potential spillover infections in other rodent species. Immunoglobulin G (IgG) antibody screening was performed using the indirect immunofluorescence assay with the Guinean Lassa virus strain Bantou 289 as antigen. The overall seroprevalence was 8% (129/1551) with the following rodents testing positive: 109 M. natalensis, seven Mastomys erythroleucus, four Lemniscomys striatus, four Praomys daltoni, three Mus minutoides, and two Praomys rostratus. Nearly all of them (122/129) originated from Bantou, Tanganya, and Gbetaya, where Lassa virus is highly endemic in M. natalensis. The antibody seroprevalence in M. natalensis from this high-endemic area (27%; 108/396) depended on the village, habitat, host age, and host abundance. A main positive factor was age; the maximum seroprevalence reached 50% in older animals. Our data fit with a model implicating that most M. natalensis rodents become horizontally infected, clear the virus within a period significantly shorter than their life span, and develop antibodies. In addition, the detection of antibodies in other species trapped in the habitats of M. natalensis suggests spillover infections. PMID:25229705

  17. The role of phylogeny in desert rodent community assembly.

    PubMed

    Brown, James H

    2012-03-01

    Recent advances in molecular genetics and phylogenetic reconstruction have the potential to transform ecology by providing new insights into the historical evolution of ecological communities. This study by Stevens and collaborators complements decades of previous research on desert rodents, by combining data from a field study and a phylogenetic tree for Mojave Desert rodents to address patterns and processes of community assembly. The number of coexisting rodent species is positively correlated, and the average phylogenetic distance among these species is negatively correlated with perennial plant species richness. As rodent species diversity increases along a gradient of increasing environmental heterogeneity, communities are composed of increasingly related species: there is a consistent pattern of phylogenetic structure from over-dispersed through random to clumped. I discuss this pattern in the light of complementary results of previous studies. This paper is noteworthy for calling attention to still unanswered questions about how the historical events of speciation, colonization, extinction, and trait evolution and their relationship to past climates and vegetation have given rise to current patterns of community organization. PMID:22324970

  18. Response of brown treesnakes to reduction of their rodent prey

    USGS Publications Warehouse

    Gragg, J.E.; Rodda, G.H.; Savidge, J.A.; White, Gary C.; Dean-Bradley, K.; Ellingson, A.R.

    2007-01-01

    Trapping brown treesnakes (Boiga irregularis; BTS) with live-mouse (Mus domesticus) lures is the principal control technique for this invasive species on Guam. Lure-based trapping is also used on other islands as a precaution against undetected arrivals and in response to verified BTS sightings. However, the effectiveness of lure-based trapping on other islands is questionable, as it has yielded no BTS despite other evidence of their presence. Some evidence suggests that high rodent numbers may interfere with BTS control. To test the relationship between rodent abundance and snake trappability, we conducted a controlled, replicated field experiment incorporating a rodenticide treatment during a BTS mark-recapture study. Using open population modeling in Program MARK, we estimated BTS apparent survival and recapture probabilities. Rodent reduction increased BTS recapture probabilities by 52-65% in 2002 and 22-36% in 2003, and it decreased apparent survival by <1% both years. This appears to be the first published instance of manipulating wild prey to influence snake behavior. Rodent reduction may enhance detection and control of BTS with traps on Guam and other islands. It may also amplify the effectiveness of oral toxicants against BTS.

  19. CONCENTRATED AMBIENT PARTICULATE STUDIES IN HEALTHY AND COMPROMISED RODENTS

    EPA Science Inventory


    CONCENTRATED AMBIENT PARTICULATE STUDIES IN HEALTHY AND COMPROMISED RODENTS. WP Watkinson1, LB Wichers2, JP Nolan1, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, LC Walsh1, ER Lappi1, D Terrell1, R Slade1, AD Ledbetter1, and DL Costa1. 1USEPA, ORD/NHEERL/ETD/PTB, RTP, NC, US...

  20. Complexity in rodent community responses to grassland-shrubland transitions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is believed that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. It has been reported, however, that a suite of biotic-abiotic interactions may inf...

  1. Lassa serology in natural populations of rodents and horizontal transmission.

    PubMed

    Fichet-Calvet, Elisabeth; Becker-Ziaja, Beate; Koivogui, Lamine; Günther, Stephan

    2014-09-01

    Lassa virus causes hemorrhagic fever in West Africa. Previously, we demonstrated by PCR screening that only the multimammate mouse, Mastomys natalensis, hosts Lassa virus in Guinea. In the present study, we used the same specimen collection from 17 villages in Coastal, Upper, and Forest Guinea to investigate the Lassa virus serology in the rodent population. The aim was to determine the dynamics of antibody development in M. natalensis and to detect potential spillover infections in other rodent species. Immunoglobulin G (IgG) antibody screening was performed using the indirect immunofluorescence assay with the Guinean Lassa virus strain Bantou 289 as antigen. The overall seroprevalence was 8% (129/1551) with the following rodents testing positive: 109 M. natalensis, seven Mastomys erythroleucus, four Lemniscomys striatus, four Praomys daltoni, three Mus minutoides, and two Praomys rostratus. Nearly all of them (122/129) originated from Bantou, Tanganya, and Gbetaya, where Lassa virus is highly endemic in M. natalensis. The antibody seroprevalence in M. natalensis from this high-endemic area (27%; 108/396) depended on the village, habitat, host age, and host abundance. A main positive factor was age; the maximum seroprevalence reached 50% in older animals. Our data fit with a model implicating that most M. natalensis rodents become horizontally infected, clear the virus within a period significantly shorter than their life span, and develop antibodies. In addition, the detection of antibodies in other species trapped in the habitats of M. natalensis suggests spillover infections. PMID:25229705

  2. RODENT AND RUMINANT INGESTIVE RESPONSES TO FLAVONOIDS IN EUPHORBIA ESULA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Euphorbia esula, common name leafy spurge, was chemically evaluated for aversive phytochemicals that appear to minimize herbivory by rodents and cattle. A portion of the initial aqueous methanol extract called the middle layer elicited food aversions in rats as did the petroleum ether extract of th...

  3. Optimizing Cardiovascular Benefits of Exercise: A Review of Rodent Models

    PubMed Central

    Davis, Brittany; Moriguchi, Takeshi; Sumpio, Bauer

    2013-01-01

    Although research unanimously maintains that exercise can ward off cardiovascular disease (CVD), the optimal type, duration, intensity, and combination of forms are yet not clear. In our review of existing rodent-based studies on exercise and cardiovascular health, we attempt to find the optimal forms, intensities, and durations of exercise. Using Scopus and Medline, a literature review of English language comparative journal studies of cardiovascular benefits and exercise was performed. This review examines the existing literature on rodent models of aerobic, anaerobic, and power exercise and compares the benefits of various training forms, intensities, and durations. The rodent studies reviewed in this article correlate with reports on human subjects that suggest regular aerobic exercise can improve cardiac and vascular structure and function, as well as lipid profiles, and reduce the risk of CVD. Findings demonstrate an abundance of rodent-based aerobic studies, but a lack of anaerobic and power forms of exercise, as well as comparisons of these three components of exercise. Thus, further studies must be conducted to determine a truly optimal regimen for cardiovascular health. PMID:24436579

  4. COMPLEMENTARITY OF GENOTOXIC AND NONGENOTOXIC PREDICTORS OF RODENT CARCINOGENICITY

    EPA Science Inventory

    Twenty-one chemicals known to be carcinogenic in rodent bioassays were selected for study. he chemicals were administered by gavage in two dose levels to female Sprague-Dawley rats. he effects of these 21 chemicals on four biochemical assays (hepatic DNA damage by alkaline elutio...

  5. Andes Hantavirus Variant in Rodents, Southern Amazon Basin, Peru

    PubMed Central

    Tokarz, Rafal; Ghersi, Bruno M.; Salmon-Mulanovich, Gabriela; Guezala, M. Claudia; Albujar, Christian; Mendoza, A. Patricia; Tinoco, Yeny O.; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Vctor; Strher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T.; Hirschberg, David L.; Lipkin, W. Ian; Bausch, Daniel G.; Montgomery, Joel M.

    2014-01-01

    We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted. PMID:24447689

  6. Evaluation of two oral baiting systems for wild rodents.

    PubMed

    Creekmore, T E; Fletcher, W O; Stallknecht, D E

    1998-04-01

    Tetracycline hydrochloride (TC)-treated peanut butter or rodent chow baits were distributed during March 1990, on separate 0.53 ha sites in Oglethorpe County, Georgia (USA). Rodents were trapped on a control site prior to bait distribution and on two baited sites 6 days post-distribution. Cleaned skulls from euthanized mammals were grossly examined for TC fluorescence using an ultraviolet (UV) light. Mandibles were sectioned and examined for TC fluorescence using an ultraviolet light microscope. All 21 cotton rats (Sigmodon hispidus), four eastern harvest mice (Rithrodontomys humulis), and two golden mice (Ochrotomys nuttalli) captured on the control site were negative for TC fluorescence. On the peanut butter bait site, mandible sections from 29 of 32 (91%) cotton rats, three of three (100%) eastern harvest mice, two of three (66%) golden mice, zero of five (0%) white-footed mice (Peromyscus leucopus), one of three (33%) short-tailed shrews (Blarina brevicauda), and zero of two (0%) least shrews (Cryptotis parva) were positive for TC. Results from the rodent chow bait site indicated that 18 of 25 (72%) cotton rats, zero of three (0%) eastern harvest mice, two of seven (29%) golden mice, zero of four (0%) white-footed mice, and zero of four (0%) least shrews were positive for TC fluorescence in mandible sections. These results suggest that a large portion of a free-ranging small rodent population can be administered biological markers or vaccines using baits. PMID:9577787

  7. Rodent Research on the International Space Station - A Look Forward

    NASA Technical Reports Server (NTRS)

    Kapusta, A. B.; Smithwick, M.; Wigley, C. L.

    2014-01-01

    Rodent Research on the International Space Station (ISS) is one of the highest priority science activities being supported by NASA and is planned for up to two flights per year. The first Rodent Research flight, Rodent Research-1 (RR-1) validates the hardware and basic science operations (dissections and tissue preservation). Subsequent flights will add new capabilities to support rodent research on the ISS. RR-1 will validate the following capabilities: animal husbandry for up to 30 days, video downlink to support animal health checks and scientific analysis, on-orbit dissections, sample preservation in RNA. Later and formalin, sample transfer from formalin to ethanol (hindlimbs), rapid cool-down and subsequent freezing at -80 of tissues and carcasses, sample return and recovery. RR-2, scheduled for SpX-6 (Winter 20142015) will add the following capabilities: animal husbandry for up to 60 days, RFID chip reader for individual animal identification, water refill and food replenishment, anesthesia and recovery, bone densitometry, blood collection (via cardiac puncture), blood separation via centrifugation, soft tissue fixation in formalin with transfer to ethanol, and delivery of injectable drugs that require frozen storage prior to use. Additional capabilities are also planned for future flights and these include but are not limited to male mice, live animal return, and the development of experiment unique equipment to support science requirements for principal investigators that are selected for flight. In addition to the hardware capabilities to support rodent research the Crew Office has implemented a training program in generic rodent skills for all USOS crew members during their pre-assignment training rotation. This class includes training in general animal handling, euthanasia, injections, and dissections. The dissection portion of this training focuses on the dissection of the spleen, liver, kidney with adrenals, brain, eyes, and hindlimbs. By achieving and maintaining proficiency in these basic skills as part of the nominal astronaut training curriculum this allows the rodent research program to focus the mission specific crew training on scientific requirements of research and operations flow.

  8. The Touchscreen Cognitive Testing Method for Rodents: How to Get the Best out of Your Rat

    ERIC Educational Resources Information Center

    Bussey, Timothy J.; Padain, Tina L.; Skillings, Elizabeth A.; Winters, Boyer D.; Morton, A. Jennifer; Saksida, Lisa M.

    2008-01-01

    The touchscreen testing method for rodents is a computer-automated behavioral testing method that allows computer graphic stimuli to be presented to rodents and the rodents to respond to the computer screen via a nose-poke directly to the stimulus. The advantages of this method are numerous; however, a systematic study of the parameters that

  9. Barnes maze testing strategies with small and large rodent models.

    PubMed

    Rosenfeld, Cheryl S; Ferguson, Sherry A

    2014-01-01

    Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g. bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g. distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e. random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g. shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug/ toxicant exposure. PMID:24637673

  10. The response of human and rodent cells to hyperthermia

    SciTech Connect

    Roizin-Towle, L.; Pirro, J.P. )

    1991-04-01

    Inherent cellular radiosensitivity in vitro has been shown to be a good predictor of human tumor response in vivo. In contrast, the importance of the intrinsic thermosensitivity of normal and neoplastic human cells as a factor in the responsiveness of human tumors to adjuvant hyperthermia has never been analyzed systematically. A comparison of thermal sensitivity and thermo-radiosensitization in four rodent and eight human-derived cell lines was made in vitro. Arrhenius plots indicated that the rodent cells were more sensitive to heat killing than the human, and the break-point was 0.5 degrees C higher for the human than rodent cells. The relationship between thermal sensitivity and the interaction of heat with X rays at low doses was documented by thermal enhancement ratios (TER's). Cells received either a 1 hr exposure to 43 degrees C or a 20 minute treatment at 45 degrees C before exposure to 300 kVp X rays. Thermal enhancement ratios ranged from 1.0 to 2.7 for human cells heated at 43 degrees C and from 2.1 to 5.3 for heat exposures at 45 degrees C. Thermal enhancement ratios for rodent cells were generally 2 to 3 times higher than for human cells, because of the fact that the greater thermosensitivity of rodent cells results in a greater enhancement of radiation damage. Intrinsic thermosensitivity of human cells has relevance to the concept of thermal dose; intrinsic thermo-radiosensitization of a range of different tumor cells is useful in documenting the interactive effects of radiation combined with heat.

  11. Survey of Hymenolepis spp. in pet rodents in Italy.

    PubMed

    d'Ovidio, D; Noviello, Emilio; Pepe, P; Del Prete, L; Cringoli, G; Rinaldi, L

    2015-12-01

    We carried out the first survey of Hymenolepis spp. infection in pet rodents in Italy. Fresh fecal samples were collected from 172 pet rodents as follows: guinea pigs (Cavia porcellus; n = 60), squirrels (Callosciurus finlaysonii, Callosciurus prevosti, Tamias striatus, Tamias sibiricus, Sciurus calorinensis; n = 52), hamsters (Phodopus campbelli, Mesocricetus auratus; n = 30), chinchillas (Chinchilla lanigera; n = 13), rats (Rattus norvegicus; n = 10), and mice (Mus minutoides; n = 7). These animals were housed either in pet shops or in private houses. All fecal samples were processed using the FLOTAC pellet technique to assess the number of eggs per gram (EPG) of feces. Eggs of Hymenolepis nana were found in 24 out of 172 (13.9 %; 95 % confidence interval = 9.3-20.2 %) pet rodents. Of those rodents, 41.6 % (10/24) were rats (mean EPG = 55.7; range = 2-200), 29.2 % (7/24) mice (mean EPG = 64.5; range = 32-120), 25.0 % (6/24) were chinchillas (mean EPG = 25.5; range = 10-50), and 4.2 % (1/24) hamsters (P. campbelli) (EPG = 86.0). In addition, Hymenolepis diminuta eggs were found in 2 out of 172 (1.2 %; 95 % confidence interval = 0.2-4.6 %) rodents examined, both of which (100 %; 2/2) were pet squirrels (C. prevosti) (mean EPG = 10; range = 4-16). To the authors' knowledge, this is the first report of a natural infection of H. diminuta in pet squirrels. PMID:26290218

  12. Nutritional Evaluation of NASA's Rodent Food Bar Diet

    NASA Technical Reports Server (NTRS)

    Barrett, Joyce E.; Yu, Diane S.; Dalton, Bonnie P.

    2000-01-01

    Tests are being conducted on NASA's rodent Food Bar in preparation for long-term use as the rat and mouse diet aboard the International Space Station. Nutritional analyses are performed after the bars are manufactured and then repeated periodically to determine nutritional stability. The primary factors analyzed are protein, ash, fat, fiber, moisture, amino acids, fatty acids, and minerals. Nutrient levels are compared to values published in the National Research Council's dietary requirements for rodents, and also to those contained in several commonly used commercial rodent lab diets. The Food Bar is manufactured from a powdered diet to which moisture is added as it is processed through an extruder. The bars are dipped into potassium sorbate, vacuum-sealed, and irradiated. In order to determine nutrient changes during extrusion and irradiation, the powdered diet, the non-irradiated bars, and the irradiated bars are all analyzed. We have observed lower values for some nutrients (iodine, vitamin K, and iron) in the Food Bars compared with NRC requirements. Many nutrients in the Food Bars are contained at a higher level than levels in the NRC requirements. An additional factor we are investigating is the 26% moisture level in the Food Bars, which drops to about 15% within a week, compared to a stable 10% moisture in many standard lab chow diets. In addition to the nutritional analyses, the food bar is being fed to several strains of rats and mice, and feeding study and necropsy results are being observed (Barrett et al, unpublished data). Information from the nutritional analyses and from the rodent studies will enable us to recommend the formulation that will most adequately meet the rodent Food Bar requirements for long-term use aboard the Space Station.

  13. Barnes Maze Testing Strategies with Small and Large Rodent Models

    PubMed Central

    2014-01-01

    Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g.bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g.distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e.random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g.shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug/ toxicant exposure. PMID:24637673

  14. CHEMICAL AND RADIATION LEUKEMOGENESIS IN HUMANS AND RODENTS AND THE VALUE OF RODENT MODELS FOR ASSESSING RISKS OF LYMPHOHEMATOPOIETIC CANCERS

    EPA Science Inventory

    This report is intended to provide an up-to-date overview of the lymphoid and hematopoietic diseases induced in humans and rodents following exposure to chemical agents. It includes a brief introduction to hematopoiesis and leukemia-inducing agents and their effects in mice and r...

  15. Intensive rainfall recharges tropical groundwaters

    NASA Astrophysics Data System (ADS)

    Jasechko, Scott; Taylor, Richard G.

    2015-12-01

    Dependence upon groundwater to meet rising agricultural and domestic water needs is expected to increase substantially across the tropics where, by 2050, over half of the world’s population is projected to live. Rare, long-term groundwater-level records in the tropics indicate that groundwater recharge occurs disproportionately from heavy rainfalls exceeding a threshold. The ubiquity of this bias in tropical groundwater recharge to intensive precipitation is, however, unknown. By relating available long-term records of stable-isotope ratios of O and H in tropical precipitation (15 sites) to those of local groundwater, we reveal that groundwater recharge in the tropics is near-uniformly (14/15 sites) biased to intensive monthly rainfall, commonly exceeding the ∼70th intensity decile. Our results suggest that the intensification of precipitation brought about by global warming favours groundwater replenishment in the tropics. Nevertheless, the processes that transmit intensive rainfall to groundwater systems and enhance the resilience of tropical groundwater storage in a warming world, remain unclear.

  16. The energetics of a Malagasy rodent, Macrotarsomys ingens (Nesomyinae): a test of island and zoogeographical effects on metabolism.

    PubMed

    Lobban, Kerileigh D; Lovegrove, Barry G; Rakotondravony, Daniel

    2014-12-01

    This study provides first insights into the energetics of the Nesomyinae, a subfamily of rodents endemic to Madagascar. The ancestral nesomyine colonized Madagascar from Africa ca. 30-15 mya at the onset of Oligocene global cooling. We tested the hypothesis that, contrary to what might be expected from Island Biogeography theory, post-colonization character displacement of thermoregulatory traits was constrained by phylogenetic inertia through climate adaptation. The study was conducted in the Parc National d'Ankarafantsika, Madagascar. We measured the basal metabolic rate (BMR) and body temperature (T b) patterns of naturally warm-acclimated, freshly captured adult long-tailed big-footed mice Macrotarsomys ingens (67.4 g). The mean ± SD BMR of M. ingens was 0.298 ± 0.032 Watts (n = 12), 31.7 % lower than that predicted by a phylogenetically independent allometric equation. Body mass was correlated with BMR. The lower critical limit of thermoneutrality (T lc) was 30.7°C. The mean ± SD T b = 36.1 ± 0.8°C (n = 12) compared well with the mean T b values for myomorph rodents from the Afrotropical zone, but was lower than those of the Neotropical and Palearctic zones. M. ingens became pathologically hypothermic when exposed to ambient temperatures lower than 18°C. The soil temperature at depths of 250 mm and deeper did not decrease below 22°C throughout the austral winter. The thermoregulatory data for M. ingens did not differ from those that characterize mainland Afrotropical rodents. However, BMR and T b were lower than those of Holarctic rodents. Thus, contrary to expectations of Island Biogeography theory that rapid character displacement often occurs in morphological and behavioural traits when mammals colonize islands, M. ingens displayed climate-related physiological traits indicative of phylogenetic inertia. Presumably the tropical conditions that prevailed on Madagascar at the time of colonisation differed very little from those of the African mainland, and hence there was no strong driving force for change. Unlike small tenrecs and lemurs that radiated on Madagascar prior to the Oligocene, traits associated with an insular existence, such as daily torpor and hibernation, were not evident in M. ingens. PMID:25189668

  17. Micro irrigation of tropical fruit crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In most tropical regions, tropical fruits are grown either in wet-and-dry climates characterized by erratic rainfall patterns and prolonged dry periods or in fertile but semiarid lands under irrigation. Little is known about water requirements of tropical crops grown in the tropics. This book chapt...

  18. [Strategies for sustainable management of commensal rodents. Definitions of control objectives at communal level].

    PubMed

    Plenge-Bnig, A; Schmolz, E

    2014-05-01

    The German Act on the Prevention and Control of Infectious Diseases in Man (Infektionsschutzgesetz, IfSG) provides a legal framework for activities and responsibilities concerning communal rodent control. However, actual governance of communal rodent control is relatively heterogeneous, as federal states (Bundeslnder) have different or even no regulations for prevention and management of commensal rodent infestations (e.g. brown rats, roof rats and house mice). Control targets and control requirements are rarely precisely defined and often do not go beyond general measures and objectives. Although relevant regulations provide information about agreed preventive measures against rodents, the concept of sustainability is not expressed as such. A centrally managed database-supported municipal rodent control is a key factor for sustainability because it allows a systematic and analytical approach to identify and reduce rodent populations. The definition of control objectives and their establishment in legal decrees is mandatory for the implementation of a sustainable management strategy of rodent populations at a local level. Systematic recording of rodent infestations through municipal-operated monitoring provides the essential data foundation for a targeted rodent management which is already implemented in some German and European cities and nationwide in Denmark. A sustainable rodent management includes a more targeted rodenticide application which in the long-term will lead to an overall reduction of rodenticide use. Thus, the benefits of sustainable rodent management will be a reduction of rodenticide exposure to the environment, prevention of resistance and long-term economical savings. PMID:24781906

  19. Tropical Ecosystems and Ecological Concepts

    NASA Astrophysics Data System (ADS)

    Osborne, Patrick L.

    2000-09-01

    Over one third of the earth's terrestrial surface is situated in the tropics, with environments ranging from hot deserts to tropical rain forests. This introductory textbook, aimed at students studying tropical ecology, provides a comprehensive guide to the major tropical biomes and is unique in its balanced coverage of both aquatic and terrestrial systems. The volume considers the human ecological dimension, covering issues such as population growth, urbanization, agriculture and fisheries, natural resource use, and pollution. It is international in scope and addresses global issues such as conservation of biodiversity, climate change, and the concept of ecological sustainability. The text is supported throughout by boxes containing supplementary material on a range of topics and organisms, mathematical concepts and calculations, and is enlivened with clear line diagrams, maps, and photographs. A cross-referenced glossary, extensive bibliography, and comprehensive index are included as further aids to study.

  20. Before Departure: Advising Tropical Travellers

    PubMed Central

    Russell, Margaret

    1990-01-01

    Advising travellers to tropical and subtropical countries before their departure requires physician use of regularly updated information sources. The author outlines an approach to risk assessment and presents an overview of important issues and some information sources. PMID:21233911

  1. Susceptibility of selected rodent species from Colorado to Borrelia burgdorferi.

    PubMed

    Ubico, S R; McLean, R G; Cooksey, L M

    1996-04-01

    To determine the susceptibility of some common Colorado (USA) rodent species to Borrelia burgdorferi, pregnant Peromyscus maniculatus, Tamias minimus, and Spermophilus lateralis were trapped in May 1990 and kept in quarantine until their young were old enough to be used in the experiment. Six to eight 8-wk-old individuals of each of the Colorado species and, for comparison, eight laboratory raised P. leucopus were subcutaneously inoculated with > or = 10(5) spirochetes in 0.1 ml in July 1990. Tissue specimens were collected for isolation from these animals through April 1991. Spirochetes were isolated from blood, ear, bladder, kidney, spleen, liver, and eye in Barbour-Stoener-Kelly (BSK) medium from P. maniculatus, P. leucopus and T. minimus. Spirochetes were isolated from at least one tissue from all of these animals and no isolations were obtained from any of the S. lateralis. Thus, three of the four rodent species tested are susceptible to, and could harbor, B. burgdorferi. PMID:8722268

  2. Hantavirus Infection in Humans and Rodents, Northwestern Argentina

    PubMed Central

    Levis, Silvana; Calderón, Gladys; Ramirez, Josefina; Bravo, Daniel; Lozano, Elena; Ripoll, Carlos; St. Jeor, Stephen; Ksiazek, Thomas G.; Barquez, Ruben M.; Enria, Delia

    2003-01-01

    We initiated a study to elucidate the ecology and epidemiology of hantavirus infections in northern Argentina. The northwestern hantavirus pulmonary syndrome (HPS)–endemic area of Argentina comprises Salta and Jujuy Provinces. Between 1997 and 2000, 30 HPS cases were diagnosed in Jujuy Province (population 512,329). Most patients had a mild clinical course, and the death rate (13.3%) was low. We performed a serologic and epidemiologic survey in residents of the area, in conjunction with a serologic study in rodents. The prevalence of hantavirus antibodies in the general human population was 6.5%, one of the highest reported in the literature. No evidence of interhuman transmission was found, and the high prevalence of hantavirus antibody seemed to be associated with the high infestation of rodents detected in domestic and peridomestic habitats. PMID:14519242

  3. Limitations to adaptive optics image quality in rodent eyes

    PubMed Central

    Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

    2012-01-01

    Adaptive optics (AO) retinal image quality of rodent eyes is inferior to that of human eyes, despite the promise of greater numerical aperture. This paradox challenges several assumptions commonly made in AO imaging, assumptions which may be invalidated by the very high power and dioptric thickness of the rodent retina. We used optical modeling to compare the performance of rat and human eyes under conditions that tested the validity of these assumptions. Results showed that AO image quality in the human eye is robust to positioning errors of the AO corrector and to differences in imaging depth and wavelength compared to the wavefront beacon. In contrast, image quality in the rat eye declines sharply with each of these manipulations, especially when imaging off-axis. However, some latitude does exist to offset these manipulations against each other to produce good image quality. PMID:22876346

  4. Short interspersed elements (SINEs) of the Geomyoidea superfamily rodents.

    PubMed

    Gogolevsky, Konstantin P; Kramerov, Dmitri A

    2006-05-24

    A new short interspersed element (SINE) was isolated from the genome of desert kangaroo rat (Dipodomys deserti) using single-primer PCR. This SINE consists of two monomers: the left monomer (IDL) resembles rodent ID element and other tRNAAla(CGC)-derived SINEs, whereas the right one (Geo) shows no similarity with known SINE sequences. PCR and hybridization analyses demonstrated that IDL-Geo SINE is restricted to the rodent superfamily Geomyoidea (families Geomyidea and Heteromyidea). Isolation and analysis of IDL-Geo from California pocket mouse (Chaetodipus californicus) and Botta's pocket gopher (Thomomys bottae) revealed some species-specific features of this SINE family. The structure and evolution of known dimeric SINEs are discussed. PMID:16517098

  5. Ultrastructural study of abnormal spermiogenesis in four hystricognate rodents.

    PubMed

    Feito, R J

    1990-03-01

    Spermatids and epididymal spermatozoa from wild burrowing hystricognate rodents were examined. Structural defects affected the acrosome, the nucleus and the tail, and were similar to those found in the developing germ cells and spermatozoa from domestic mammals and man. The acrosome vesiculation of epididymal spermatozoa from hystricognate rodents might not be necessarily an abnormality and may represent a step in the acrosome reaction. Major abnormalities, such as invagination of the acrosome granule, incorporation of lytic vesicles into the forming acrosome, detachment of the acrosome from the flat surfaces of the nucleus, invagination of the nuclear envelope, and the occurrence of multinucleated and multitailed elements may be caused by a variety of factors, but those related to seasonal reproduction (breeding season) should not be neglected. PMID:2325011

  6. Experimental infections by Brucella suis type 4 in Alaskan rodents.

    PubMed

    Miller, L G; Neiland, K A

    1980-10-01

    The susceptibility of nine species of rodents and one species of lagomorph to Brucella suis type 4 was studied experimentally. The rodent species included: guinea pig (Cavia porcellus), Scandinavian lemming (Lemmus lemmus), brown lemming (L. sibiricus), northern red-backed vole (Clethrionomys rutilis), varying lemmings (Dicrostonyx stevensoni and D. rubricatus), yellow-cheeked vole (Microtus xanthognathus), flying squirrel (Glaucomys sabrinus) and ground squirrel (Citellus parryii). The lagomorph, Lepus americanus (varying hare), was also studied. All of these species were readily infected by intraperitoneal inoculations of brucellae. Pathologic responses were not marked in most of these species. However, both species of varying lemmings responded dramatically to infections initiated by about as few as two cfu. All individuals of both species that were not killed eventually died from the infection. PMID:7463596

  7. Enteric pathogens in tropical aquaria.

    PubMed Central

    Sanyal, D.; Burge, S. H.; Hutchings, P. G.

    1987-01-01

    A total of 100 tropical aquaria from six pet shops were sampled for the presence of Salmonella, Campylobacter and Aeromonas species. Eight fish tanks contained unusual serotypes of salmonella. None had been used to house terrapins. One hundred and three isolates of Aeromonas species were obtained from 98 tanks. One tank contained Plesiomonas shigelloides. No Campylobacter species were isolated. It is suggested that a tropical aquarium may constitute an infection hazard. PMID:3428370

  8. Hydrology of a Tropical Peatland

    NASA Astrophysics Data System (ADS)

    Cobb, A.; Gandois, L.; Abu Salim, K.; Harvey, C. F.

    2011-12-01

    The hydrology of tropical peat forests is tied closely to decomposition processes in the soil and thus to the role of these forests as sinks of atmospheric carbon. We present results from an ongoing study on the hydrology and carbon cycle of a tropical peat forest in Brunei Darussalam. Data from rain gauges and well piezometers are combined with meteorological data for a preliminary hydrological balance.

  9. Tropical Cyclone Gonu

    NASA Technical Reports Server (NTRS)

    2007-01-01

    You might expect to see a storm with near-perfect symmetry and a well-defined eye hovering over the warm waters of the Caribbean or in the South Pacific, but Tropical Cyclone Gonu showed up in an unusual place. On June 4, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this image, Tropical Cyclone Gonu was approaching the northeastern shore of Oman, a region better known for hot desert conditions. Though rare, cyclones like Gonu are not unheard of in the northern Indian Ocean basin. Most cyclones that form in the region form over the Bay of Bengal, east of India. Those that take shape over the Arabian Sea, west of the Indian peninsula, tend to be small and fizzle out before coming ashore. Cyclone Gonu is a rare exception. As of June 4, 2007, the powerful storm had reached a dangerous Category Four status, and it was forecast to graze Oman's northeastern shore, following the Gulf of Oman. According to storm statistics maintained on Unisys Weather, the last storm of this size to form over the Arabian Sea was Cyclone 01A, which tracked northwest along the coast of India between May 21 and May 28, 2001. Unlike Gonu's forecasted track, Cyclone 01A never came ashore. MODIS acquired this photo-like image at 12:00 p.m. local time (9:00 UTC), a few hours after the Joint Typhoon Warning Center estimated Gonu's sustained winds to be over 240 kilometers per hour (145 miles per hour). The satellite image confirms that Gonu was a super-powerful cyclone. The storm has the hallmark tightly wound arms that spiral around a well-defined, circular eye. The eye is surrounded by a clear wall of towering clouds that cast shadows on the surrounding clouds. Called hot towers, these clouds are a sign of the powerful uplift that feeds the storm. The symmetrical spirals, clear eye, and towering clouds are all features regularly seen in satellite images of other particularly powerful cyclones, which are also known as typhoons or hurricanes when they form in other parts of the world. The high-resolution image provided above is at MODIS' full spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response System provides this image at additional resolutions.

  10. Miniature wireless recording and stimulation system for rodent behavioural testing

    NASA Astrophysics Data System (ADS)

    Pinnell, R. C.; Dempster, J.; Pratt, J.

    2015-12-01

    Objective. Elucidation of neural activity underpinning rodent behaviour has traditionally been hampered by the use of tethered systems and human involvement. Furthermore the combination of deep-brain stimulation (DBS) and various neural recording modalities can lead to complex and time-consuming laboratory setups. For studies of this type, novel tools are required to drive forward this research. Approach. A miniature wireless system weighing 8.5 g (including battery) was developed for rodent use that combined multichannel DBS and local-field potential (LFP) recordings. Its performance was verified in a working memory task that involved 4-channel fronto-hippocampal LFP recording and bilateral constant-current fimbria-fornix DBS. The system was synchronised with video-tracking for extraction of LFP at discrete task phases, and DBS was activated intermittently at discrete phases of the task. Main results. In addition to having a fast set-up time, the system could reliably transmit continuous LFP at over 8 hours across 3-5 m distances. During the working memory task, LFP pertaining to discrete task phases was extracted and compared with well-known neural correlates of active exploratory behaviour in rodents. DBS could be wirelessly activated/deactivated at any part of the experiment during EEG recording and transmission, allowing for a seamless integration of this modality. Significance. The wireless system combines a small size with a level of robustness and versatility that can greatly simplify rodent behavioural experiments involving EEG recording and DBS. Designed for versatility and simplicity, the small size and low-cost of the system and its receiver allow for enhanced portability, fast experimental setup times, and pave the way for integration with more complex behaviour.

  11. Neurogenetics of Aggressive Behavior – Studies in Rodents

    PubMed Central

    Takahashi, Aki; Miczek, Klaus A.

    2014-01-01

    Aggressive behavior is observed in many animal species, such as insects, fish, lizards, frogs, and most mammals including humans. This wide range of conservation underscores the importance of aggressive behavior in the animals’ survival and fitness, and the likely heritability of this behavior. Although typical patterns of aggressive behavior differ between species, there are several concordances in the neurobiology of aggression among rodents, primates, and humans. Studies with rodent models may eventually help us to understand the neurogenetic architecture of aggression in humans. However, it is important to recognize the difference between the ecological and ethological significance of aggressive behavior (species-typical aggression) and maladaptive violence (escalated aggression) when applying the findings of aggression research using animal models to human or veterinary medicine. Well-studied rodent models for aggressive behavior in the laboratory setting include the mouse (Mus musculus), rat (Rattus norvegicus), hamster (Mesocricetus auratus), and prairie vole (Microtus ochrogaster). The neural circuits of rodent aggression have been gradually elucidated by several techniques e.g. immunohistochemistry of immediate-early gene (c-Fos) expression, intracranial drug microinjection, in vivo microdialysis, and optogenetics techniques. Also, evidence accumulated from the analysis of gene-knockout mice shows the involvement of several genes in aggression. Here we review the brain circuits that have been implicated in aggression, such as the hypothalamus, prefrontal cortex (PFC), dorsal raphe nucleus (DRN), nucleus accumbens (NAc), and olfactory system. We then discuss the roles of glutamate and γ-aminobutyric acid (GABA), major inhibitory and excitatory amino acids in the brain, as well as their receptors, in controlling aggressive behavior, focusing mainly on recent findings. At the end of this chapter, we discuss how genes can be identified that underlie individual differences in aggression, using the so-called forward genetics approach. PMID:24318936

  12. Challenges in tropical plant nematology.

    PubMed

    De Waele, Dirk; Elsen, Annemie

    2007-01-01

    A major challenge facing agricultural scientists today is the need to secure food for an increasing world population. This growth occurs predominantly in developing, mostly tropical countries, where the majority of hungry people live. Reducing yield losses caused by pathogens of tropical agricultural crops is one measure that can contribute to increased food production. Although plant-parasitic nematodes are often not as important as some other biotic and nonbiotic constraints on crop production in the tropics, they can nevertheless cause extensive damage and substantial yield losses. The effects of agricultural, environmental, socioeconomic, and policy changes on the occurrence of plant-parasitic nematodes in the tropics and the losses these pathogens cause are largely undocumented. Recent developments pose new challenges to tropical nematology. The increased application of molecular diagnostics may widen the knowledge gap between nematologists working in developed countries and in the tropics. Uncertainties concerning the validity of nematode species will lead to practical problems related to quarantine measures and nematode management. The study of interactions between nematodes and other pathogens in disease complexes provide opportunities for multidisciplinary research with scientists from other disciplines but remain underexploited. Difficulties in recognizing emerging nematode threats prevent the timely implementation of management strategies, thus increasing yield losses. Research is needed to address these challenges. Examples are presented mainly but not exclusively from banana, peanut, and rice nematology. PMID:17489690

  13. Experimental models of renal calcium stones in rodents.

    PubMed

    Bilbault, Héloïse; Haymann, Jean-Philippe

    2016-03-01

    In human nephrolithiasis, most stones are containing calcium and are located within urinary cavities; they may contain monohydrate calcium oxalate, dihydrate calcium oxalate and/or calcium phosphates in various proportion. Nephrolithiasis may also be associated with nephrocalcinosis, i.e., crystal depositions in tubular lumen and/or interstitium, an entity which suggests specific pathological processes. Several rodents models have been developed in order to study the pathophysiology of intrarenal crystal formation. We review here calcium rodent models classified upon the presence of nephrolithiasis and/or nephrocalcinosis. As rodents are not prone to nephrolithiasis, models require the induction of a long standing hypercalciuria or hyperoxaluria (thus explaining the very few studies reported), conversely to nephrocalcinosis which may occur within hours or days. Whereas a nephrotoxicity leading to tubular injury and regeneration appears as a critical event for crystal retention in nephrocalcinosis models, surprisingly very little is known about the physiopathology of crystal attachment to urothelium in nephrolithiasis. Creating new models of nephrolithiasis especially in different genetic mice strains appears an important challenge in order to unravel the early mechanisms of urinary stone formation in papilla and fornices. PMID:26981444

  14. Experimental models of renal calcium stones in rodents

    PubMed Central

    Bilbault, Héloïse; Haymann, Jean-Philippe

    2016-01-01

    In human nephrolithiasis, most stones are containing calcium and are located within urinary cavities; they may contain monohydrate calcium oxalate, dihydrate calcium oxalate and/or calcium phosphates in various proportion. Nephrolithiasis may also be associated with nephrocalcinosis, i.e., crystal depositions in tubular lumen and/or interstitium, an entity which suggests specific pathological processes. Several rodents models have been developed in order to study the pathophysiology of intrarenal crystal formation. We review here calcium rodent models classified upon the presence of nephrolithiasis and/or nephrocalcinosis. As rodents are not prone to nephrolithiasis, models require the induction of a long standing hypercalciuria or hyperoxaluria (thus explaining the very few studies reported), conversely to nephrocalcinosis which may occur within hours or days. Whereas a nephrotoxicity leading to tubular injury and regeneration appears as a critical event for crystal retention in nephrocalcinosis models, surprisingly very little is known about the physiopathology of crystal attachment to urothelium in nephrolithiasis. Creating new models of nephrolithiasis especially in different genetic mice strains appears an important challenge in order to unravel the early mechanisms of urinary stone formation in papilla and fornices. PMID:26981444

  15. Diversities of transport of sodium in rodent red cells.

    PubMed

    Willis, J S; Xu, W; Zhao, Z

    1992-08-01

    1. Na-K pumps of rodent red cells reveal variations among species in terms of kinetic properties such as ouabain sensitivity, Na/K coupling and temperature sensitivity and variations within an individual organism related to such physiological challenges as K deficiency, calorie deficiency and seasonal changes in temperature. 2. Passive Na entry among rodents collectively occurs through the same routes as in red cells of other mammals, but red cells of hamsters, rats and thirteen-lined ground squirrels lack or are deficient in an amiloride-sensitive, shrinkage-activated Na-H exchange. 3. In guinea-pig this pathway appears to be both activated and uncoupled by cooling from 37 to 20 degrees C. 4. Red cells of rodents in general and hamsters in particular are rich in a Na-Mg exchange pathway. In hamsters, this appears to be the only amiloride-sensitive pathway in simple media. 5. In hamster cells, Na entry through the amiloride-sensitive Mg-activated pathway exhibits the same kinetics as previously shown for Na activation of Mg extrusion. PMID:1355023

  16. Herbivorous rodents (Neotoma spp.) harbour abundant and active foregut microbiota.

    PubMed

    Kohl, Kevin D; Miller, Aaron W; Marvin, James E; Mackie, Roderick; Dearing, M Denise

    2014-09-01

    Symbiotic gut microbes have facilitated the success of herbivorous mammals, which are generally grouped into foregut- and hindgut-fermenters. However, rodents are primarily herbivorous and exhibit a variety of gastrointestinal anatomies. Most rodents house microbes in hindgut chambers, such as the caecum and colon. Some rodents also exhibit stomach segmentation with a foregut chamber proximal to the stomach. For over a century, scientists have hypothesized that this foregut chamber houses a microbial community, yet this has never been explicitly examined. We investigated the capacity of each of the gut regions to house microbes by measuring size, pH, bacterial cell density, concentrations of microbial metabolites and digesta transit time in woodrats (Neotoma spp.). We also compared microbial communities across gut chambers, as well as faeces, using 16S rRNA sequencing. This allowed us to test the appropriateness of using faeces as a proxy for microbial communities of other gut chambers. We found that woodrats house foregut microbial communities with similar density and volatile fatty acid concentrations to rumen ecosystems. Resident microbial communities varied between gut chambers, and faecal bacterial communities were significantly different from caecal and colonic communities. The foregut microbiota may provide a number of physiological services to the host. PMID:24373154

  17. Rodent Brain Microinjection to Study Molecular Substrates of Motivated Behavior

    PubMed Central

    Poland, Ryan S.; Bull, Cecilia; Syed, Wahab A.; Bowers, M. Scott

    2015-01-01

    Brain microinjection can aid elucidation of the molecular substrates of complex behaviors, such as motivation. For this purpose rodents can serve as appropriate models, partly because the response to behaviorally relevant stimuli and the circuitry parsing stimulus-action outcomes is astonishingly similar between humans and rodents. In studying molecular substrates of complex behaviors, the microinjection of reagents that modify, augment, or silence specific systems is an invaluable technique. However, it is crucial that the microinjection site is precisely targeted in order to aid interpretation of the results. We present a method for the manufacture of surgical implements and microinjection needles that enables accurate microinjection and unlimited customizability with minimal cost. Importantly, this technique can be successfully completed in awake rodents if conducted in conjunction with other JoVE articles that covered requisite surgical procedures. Additionally, there are many behavioral paradigms that are well suited for measuring motivation. The progressive ratio is a commonly used method that quantifies the efficacy of a reinforcer to maintain responding despite an (often exponentially) increasing work requirement. This assay is sensitive to reinforcer magnitude and pharmacological manipulations, which allows reinforcing efficacy and/ or motivation to be determined. We also present a straightforward approach to program operant software to accommodate a progressive ratio reinforcement schedule. PMID:26437131

  18. Genotypes of pathogenic Leptospira spp isolated from rodents in Argentina.

    PubMed

    Loffler, Sylvia Grune; Pavan, Maria Elisa; Vanasco, Bibiana; Samartino, Luis; Suarez, Olga; Auteri, Carmelo; Romero, Graciela; Brihuega, Bibiana

    2014-04-01

    Leptospirosis is the most widespread zoonosis in the world and significant efforts have been made to determine and classify pathogenic Leptospira strains. This zoonosis is maintained in nature through chronic renal infections of carrier animals, with rodents and other small mammals serving as the most important reservoirs. Additionally, domestic animals, such as livestock and dogs, are significant sources of human infection. In this study, a multiple-locus variable-number tandem repeat analysis (MLVA) was applied to genotype 22 pathogenic Leptospira strains isolated from urban and periurban rodent populations from different regions of Argentina. Three MLVA profiles were identified in strains belonging to the species Leptospira interrogans (serovars Icterohaemorrhagiae and Canicola); one profile was observed in serovar Icterohaemorrhagiae and two MLVA profiles were observed in isolates of serovars Canicola and Portlandvere. All strains belonging to Leptospira borgpetersenii serovar Castellonis exhibited the same MLVA profile. Four different genotypes were isolated from urban populations of rodents, including both mice and rats and two different genotypes were isolated from periurban populations. PMID:24676656

  19. Genotypes of pathogenic Leptospira spp isolated from rodents in Argentina

    PubMed Central

    Loffler, Sylvia Grune; Pavan, Maria Elisa; Vanasco, Bibiana; Samartino, Luis; Suarez, Olga; Auteri, Carmelo; Romero, Graciela; Brihuega, Bibiana

    2014-01-01

    Leptospirosis is the most widespread zoonosis in the world and significant efforts have been made to determine and classify pathogenic Leptospira strains. This zoonosis is maintained in nature through chronic renal infections of carrier animals, with rodents and other small mammals serving as the most important reservoirs. Additionally, domestic animals, such as livestock and dogs, are significant sources of human infection. In this study, a multiple-locus variable-number tandem repeat analysis (MLVA) was applied to genotype 22 pathogenic Leptospira strains isolated from urban and periurban rodent populations from different regions of Argentina. Three MLVA profiles were identified in strains belonging to the species Leptospira interrogans (serovars Icterohaemorrhagiae and Canicola); one profile was observed in serovar Icterohaemorrhagiae and two MLVA profiles were observed in isolates of serovars Canicola and Portlandvere. All strains belonging to Leptospira borgpetersenii serovar Castellonis exhibited the same MLVA profile. Four different genotypes were isolated from urban populations of rodents, including both mice and rats and two different genotypes were isolated from periurban populations. PMID:24676656

  20. Rodent Brain Microinjection to Study Molecular Substrates of Motivated Behavior.

    PubMed

    Poland, Ryan S; Bull, Cecilia; Syed, Wahab A; Bowers, M Scott

    2015-01-01

    Brain microinjection can aid elucidation of the molecular substrates of complex behaviors, such as motivation. For this purpose rodents can serve as appropriate models, partly because the response to behaviorally relevant stimuli and the circuitry parsing stimulus-action outcomes is astonishingly similar between humans and rodents. In studying molecular substrates of complex behaviors, the microinjection of reagents that modify, augment, or silence specific systems is an invaluable technique. However, it is crucial that the microinjection site is precisely targeted in order to aid interpretation of the results. We present a method for the manufacture of surgical implements and microinjection needles that enables accurate microinjection and unlimited customizability with minimal cost. Importantly, this technique can be successfully completed in awake rodents if conducted in conjunction with other JoVE articles that covered requisite surgical procedures. Additionally, there are many behavioral paradigms that are well suited for measuring motivation. The progressive ratio is a commonly used method that quantifies the efficacy of a reinforcer to maintain responding despite an (often exponentially) increasing work requirement. This assay is sensitive to reinforcer magnitude and pharmacological manipulations, which allows reinforcing efficacy and/ or motivation to be determined. We also present a straightforward approach to program operant software to accommodate a progressive ratio reinforcement schedule. PMID:26437131

  1. Rodent models for resolving extremes of exercise and health.

    PubMed

    Garton, Fleur C; North, Kathryn N; Koch, Lauren G; Britton, Steven L; Nogales-Gadea, Gisela; Lucia, Alejandro

    2016-02-01

    The extremes of exercise capacity and health are considered a complex interplay between genes and the environment. In general, the study of animal models has proven critical for deep mechanistic exploration that provides guidance for focused and hypothesis-driven discovery in humans. Hypotheses underlying molecular mechanisms of disease and gene/tissue function can be tested in rodents to generate sufficient evidence to resolve and progress our understanding of human biology. Here we provide examples of three alternative uses of rodent models that have been applied successfully to advance knowledge that bridges our understanding of the connection between exercise capacity and health status. First we review the strong association between exercise capacity and all-cause morbidity and mortality in humans through artificial selection on low and high exercise performance in the rat and the consequent generation of the "energy transfer hypothesis." Second we review specific transgenic and knockout mouse models that replicate the human disease condition and performance. This includes human glycogen storage diseases (McArdle and Pompe) and ?-actinin-3 deficiency. Together these rodent models provide an overview of the advancements of molecular knowledge required for clinical translation. Continued study of these models in conjunction with human association studies will be critical to resolving the complex gene-environment interplay linking exercise capacity, health, and disease. PMID:26395598

  2. Rodent Models of Depression: Neurotrophic and Neuroinflammatory Biomarkers

    PubMed Central

    Stepanichev, Mikhail; Dygalo, Nikolay N.; Grigoryan, Grigory; Shishkina, Galina T.; Gulyaeva, Natalia

    2014-01-01

    Rodent models are an indispensable tool for studying etiology and progress of depression. Since interrelated systems of neurotrophic factors and cytokines comprise major regulatory mechanisms controlling normal brain plasticity, impairments of these systems form the basis for development of cerebral pathologies, including mental diseases. The present review focuses on the numerous experimental rodent models of depression induced by different stress factors (exteroceptive and interoceptive) during early life (including prenatal period) or adulthood, giving emphasis to the data on the changes of neurotrophic factors and neuroinflammatory indices in the brain. These parameters are closely related to behavioral depression-like symptoms and impairments of neuronal plasticity and are both gender- and genotype-dependent. Stress-related changes in expression of neurotrophins and cytokines in rodent brain are region-specific. Some contradictory data reported by different groups may be a consequence of differences of stress paradigms or their realization in different laboratories. Like all experimental models, stress-induced depression-like conditions are experimental simplification of clinical depression states; however, they are suitable for understanding the involvement of neurotrophic factors and cytokines in the pathogenesis of the disease—a goal unachievable in the clinical reality. These major regulatory systems may be important targets for therapeutic measures as well as for development of drugs for treatment of depression states. PMID:24999483

  3. Principles of rodent surgery for the new surgeon.

    PubMed

    Pritchett-Corning, Kathleen R; Luo, Yiying; Mulder, Guy B; White, William J

    2011-01-01

    For both scientific and animal welfare reasons, training in basic surgical concepts and techniques should be undertaken before ever seeking to perform surgery on a rodent. Students, post-doctoral scholars, and others interested in performing surgery on rodents as part of a research protocol may not have had formal surgical training as part of their required coursework. Surgery itself is a technical skill, and one that will improve with practice. The principles of aseptic technique, however, often remain unexplained or untaught. For most new surgeons, this vital information is presented in piecemeal fashion or learned on the job, neither of which is ideal. It may also make learning how to perform a particular surgery difficult, as the new surgeon is learning both a surgical technique and the principles of asepsis at the same time. This article summarizes and makes recommendations for basic surgical skills and techniques necessary for successful rodent surgery. This article is designed to supplement hands-on training by the user's institution. PMID:21248700

  4. L1 expression and regulation in humans and rodents

    PubMed Central

    Rosser, James M.; An, Wenfeng

    2015-01-01

    Long interspersed elements type 1 (LINE-1s, or L1s) have impacted mammalian genomes at multiple levels. L1 transcription is mainly controlled by its 5’ untranslated region (5’UTR), which differs significantly among active human and rodent L1 families. In this review, L1 expression and its regulation are examined in the context of human and rodent development. First, endogenous L1 expression patterns in three different species—human, rat, and mouse—are compared and contrasted. A detailed account of relevant experimental evidence is presented according to the source material, such as cell lines, tumors, and normal somatic and germline tissues from different developmental stages. Second, factors involved in the regulation of L1 expression at both transcriptional and posttranscriptional levels are discussed. These include transcription factors, DNA methylation, PIWI-interacting RNAs (piRNAs), RNA interference (RNAi), and posttranscriptional host factors. Similarities and differences between human and rodent L1s are highlighted. Third, recent findings from transgenic mouse models of L1 are summarized and contrasted with those from endogenous L1 studies. Finally, the challenges and opportunities for L1 mouse models are discussed. PMID:22202032

  5. Performance analysis of exam gloves used for aseptic rodent surgery.

    PubMed

    LeMoine, Dana M; Bergdall, Valerie K; Freed, Carrie

    2015-05-01

    Aseptic technique includes the use of sterile surgical gloves for survival surgeries in rodents to minimize the incidence of infections. Exam gloves are much less expensive than are surgical gloves and may represent a cost-effective, readily available option for use in rodent surgery. This study examined the effectiveness of surface disinfection of exam gloves with 70% isopropyl alcohol or a solution of hydrogen peroxide and peracetic acid (HP-PA) in reducing bacterial contamination. Performance levels for asepsis were met when gloves were negative for bacterial contamination after surface disinfection and sham 'exertion' activity. According to these criteria, 94% of HP-PA-disinfected gloves passed, compared with 47% of alcohol-disinfected gloves. In addition, the effect of autoclaving on the integrity of exam gloves was examined, given that autoclaving is another readily available option for aseptic preparation. Performance criteria for glove integrity after autoclaving consisted of: the ability to don the gloves followed by successful simulation of wound closure and completion of stretch tests without tearing or observable defects. Using this criteria, 98% of autoclaved nitrile exam gloves and 76% of autoclaved latex exam gloves met performance expectations compared with the performance of standard surgical gloves (88% nitrile, 100% latex). The results of this study support the use of HP-PA-disinfected latex and nitrile exam gloves or autoclaved nitrile exam gloves as viable cost-effective alternatives to sterile surgical gloves for rodent surgeries. PMID:26045458

  6. Performance Analysis of Exam Gloves Used for Aseptic Rodent Surgery

    PubMed Central

    LeMoine, Dana M; Bergdall, Valerie K; Freed, Carrie

    2015-01-01

    Aseptic technique includes the use of sterile surgical gloves for survival surgeries in rodents to minimize the incidence of infections. Exam gloves are much less expensive than are surgical gloves and may represent a cost-effective, readily available option for use in rodent surgery. This study examined the effectiveness of surface disinfection of exam gloves with 70% isopropyl alcohol or a solution of hydrogen peroxide and peracetic acid (HP–PA) in reducing bacterial contamination. Performance levels for asepsis were met when gloves were negative for bacterial contamination after surface disinfection and sham ‘exertion’ activity. According to these criteria, 94% of HP–PA-disinfected gloves passed, compared with 47% of alcohol-disinfected gloves. In addition, the effect of autoclaving on the integrity of exam gloves was examined, given that autoclaving is another readily available option for aseptic preparation. Performance criteria for glove integrity after autoclaving consisted of: the ability to don the gloves followed by successful simulation of wound closure and completion of stretch tests without tearing or observable defects. Using this criteria, 98% of autoclaved nitrile exam gloves and 76% of autoclaved latex exam gloves met performance expectations compared with the performance of standard surgical gloves (88% nitrile, 100% latex). The results of this study support the use of HP–PA-disinfected latex and nitrile exam gloves or autoclaved nitrile exam gloves as viable cost-effective alternatives to sterile surgical gloves for rodent surgeries. PMID:26045458

  7. Rodent Facial Nerve Recovery After Selected Lesions and Repair Techniques

    PubMed Central

    Hadlock, Tessa A.; Kowaleski, Jeffrey; Lo, David; Mackinnon, Susan E.; Heaton, James T.

    2015-01-01

    Background Measuring rodent facial movements is a reliable method for studying recovery from facial nerve manipulation, and for examining the behavioral correlates of aberrant regeneration. We quantitatively compared recovery of vibrissal and ocular function following three types of clinically relevant nerve injury. Methods 178 adult rats underwent facial nerve manipulation and testing. In the experimental groups, the left facial nerve was either crushed, transected and repaired epineurially, or transected and the stumps suture-secured into a tube with a 2 mm gap between them. Facial recovery was measured for the ensuing 1–4 months. Data were analyzed for whisking recovery. Previously developed markers of co-contraction of the upper and midfacial zones (possible synkinesis markers) were also examined. Results Animals in the crush groups recovered nearly normal whisking parameters within 25 days. The distal branch crush group showed improved recovery over the main trunk crush group for several days during early recovery. By week 9, the transection/repair groups showed evidence of recovery that trended further upward throughout the study period. The entubulation groups followed a similar recovery pattern, though they did not maintain significant recovery levels by the study conclusion. Markers of potential synkinesis increased in selected groups following facial nerve injury. Conclusions Rodent vibrissial function recovers in a predictable fashion following manipulation. Generalized co-contraction of the upper and midfacial zones emerges following facial nerve manipulation, possibly related to aberrant regeneration, polyterminal axons, or hypersensitivity of the rodent to sensory stimuli following nerve manipulation. PMID:20048604

  8. Rodent models of binge eating: are they models of addiction?

    PubMed

    Corwin, Rebecca L W; Babbs, R Keith

    2012-01-01

    Are recently developed rodent models of binge eating also models of food addiction? Valid models should meet human criteria for both bingeing and substance dependence as described in the 4th edition and proposed for the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM). Similarly, behavioral profiles of bingeing animals should share characteristics with those of animal models of drug addiction. We evaluate and discuss current rodent models of bingeing, their contributions to scientific understanding of bingeing, their validity with respect to DSM criteria, and their overlap with models of addiction. The models described indicate that repeated intermittent bouts in which large quantities of fatty or sugary foods are consumed (binges) are associated with behavioral changes similar to those described for drugs of abuse. In contrast, control groups consuming the same foods in a nonbinge-type manner do not exhibit an "addiction-like" behavioral profile. Thus, fatty/sugary foods in and of themselves do not appear to have addictive qualities. Rather, the manner in which they are consumed appears to be critical. In addition, while rodent models of bingeing and drug self-administration share similarities, we do not support reclassifying the bingeing-related eating disorders as substance use disorders because of differences that distinguish such disorders in humans. PMID:23520597

  9. Rodent damage to natural and replanted mountain forest regeneration.

    PubMed

    Heroldov, Marta; Bryja, Josef; Jnov, Eva; Suchomel, Josef; Homolka, Miloslav

    2012-01-01

    Impact of small rodents on mountain forest regeneration was studied in National Nature Reserve in the Beskydy Mountains (Czech Republic). A considerable amount of bark damage was found on young trees (20%) in spring after the peak abundance of field voles (Microtus agrestis) in combination with long winter with heavy snowfall. In contrast, little damage to young trees was noted under high densities of bank voles (Myodes glareolus) with a lower snow cover the following winter. The bark of deciduous trees was more attractive to voles (22% damaged) than conifers (8%). Young trees growing in open and grassy localities suffered more damage from voles than those under canopy of forest stands (? = 44.04, P < 0.001). Natural regeneration in Nature Reserve was less damaged compared to planted trees (? = 55.89, P < 0.001). The main factors influencing the impact of rodent species on tree regeneration were open, grassy habitat conditions, higher abundance of vole species, tree species preferences- and snow-cover condition. Under these conditions, the impact of rodents on forest regeneration can be predicted. Foresters should prefer natural regeneration to the artificial plantings. PMID:22666163

  10. Isolating human DNA repair genes using rodent-cell mutants

    SciTech Connect

    Thompson, L.H.; Weber, C.A.; Brookman, K.W.; Salazar, E.P.; Stewart, S.A.; Mitchell, D.L.

    1987-03-23

    The DNA repair systems of rodent and human cells appear to be at least as complex genetically as those in lower eukaryotes and bacteria. The use of mutant lines of rodent cells as a means of identifying human repair genes by functional complementation offers a new approach toward studying the role of repair in mutagenesis and carcinogenesis. In each of six cases examined using hybrid cells, specific human chromosomes have been identified that correct CHO cell mutations affecting repair of damage from uv or ionizing radiations. This finding suggests that both the repair genes and proteins may be virtually interchangeable between rodent and human cells. Using cosmid vectors, human repair genes that map to chromosome 19 have cloned as functional sequences: ERCC2 and XRCC1. ERCC1 was found to have homology with the yeast excision repair gene RAD10. Transformants of repair-deficient cell lines carrying the corresponding human gene show efficient correction of repair capacity by all criteria examined. 39 refs., 1 fig., 1 tab.

  11. Feedback-related negativity observed in rodent anterior cingulate cortex.

    PubMed

    Warren, Christopher M; Hyman, James M; Seamans, Jeremy K; Holroyd, Clay B

    2015-01-01

    The feedback-related negativity (FRN) refers to a difference in the human event-related potential (ERP) elicited by feedback indicating success versus failure: the difference appears negative when subtracting the success ERP from the failure ERP (Miltner et al., 1997). Although source localization techniques (e.g., BESA) suggest that the FRN is produced in the ACC, the inverse problem (that any given scalp distribution can be produced by an infinite number of possible dipole configurations) limits the certainty of this conclusion. The inverse problem can be circumvented by directly recording from the ACC in animal models. Although a non-human primate homologue of the FRN has been observed in the macaque monkey (e.g. Emeric et al., 2008), a homologue of the FRN has yet to be identified in rodents. We recorded local field potentials (LFPs) directly from the ACC in 6 rodents in a task based on the FRN paradigm. The animals were trained to poke their nose into a lighted port and received a feedback smell indicating whether or not a reward pellet would drop 1.5s later. We observed a FRN-like effect time-locked to the feedback scent whereby the LFP to feedback predicting no-reward was significantly more negative than the LFP to feedback predicting reward. This deflection began on average 130ms before behavioral changes in response to the feedback. Thus, we provide the first evidence of the existence of a rodent homologue of the FRN. PMID:25237010

  12. Quantification of Adiposity in Small Rodents using Micro-CT

    PubMed Central

    Judex, S.; Luu, Y.K.; Ozcivici, E.; Adler, B.; Lublinsky, S.; Rubin, C.T.

    2009-01-01

    Non-invasive three-dimensional imaging of live rodents is a powerful research tool that has become critical for advances in many biomedical fields. For investigations into adipose development, obesity, or diabetes, accurate and precise techniques that quantify adiposity in vivo are critical. Because total body fat mass does not accurately predict health risks associated with the metabolic syndrome, imaging modalities should be able to stratify total adiposity into subcutaneous and visceral adiposity. Micro-computed tomography (micro-CT) acquires high-resolution images based on the physical density of the material and can readily discriminate between subcutaneous and visceral fat. Here, a micro-CT based method to image the adiposity of live rodents is described. An automated and validated algorithm to quantify the volume of discrete fat deposits from the computed tomography is available. Data indicate that scanning the abdomen provides sufficient information to estimate total body fat. Very high correlations between micro-CT determined adipose volumes and the weight of explanted fat pads demonstrate that micro-CT can accurately monitor site-specific changes in adiposity. Taken together, in vivo micro-CT is a non-invasive, highly quantitative imaging modality with greater resolution and selectivity, but potentially lower through-put, than many other methods to precisely determine total and regional adipose volumes and fat infiltration in live rodents. PMID:19523519

  13. Tropical Cyclone Indlala

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On March 14, 2007, storm-weary Madagascar braced for its fourth land-falling tropical cyclone in as many months. Cyclone Indlala was hovering off the island's northeast coast when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this photo-like image at 1:40 p.m. local time (10:40 UTC). Just over a hundred kilometers offshore, the partially cloudy eye at the heart of the storm seems like a vast drain sucking in a disk of swirling clouds. According to reports from the Joint Typhoon Warning Center issued less than three hours after MODIS captured this image, Indlala had winds of 115 knots (132 miles per hour), with gusts up to 140 knots (161 mph). Wave heights were estimated to be 36 feet. At the time of the report, the storm was predicted to intensify through the subsequent 12-hour period, to turn slightly southwest, and to strike eastern Madagascar as a Category 4 storm with sustained winds up to 125 knots (144 mph), and gusts up to 150 knots (173 mph). According to Reuters AlertNet news service, Madagascar's emergency response resources were taxed to their limit in early March 2007 as a result of extensive flooding in the North, drought and food shortages in the South, and three previous hits from cyclones in the preceding few months: Bondo in December 2006, Clovis in January 2007, and Gamede in February.

  14. Results from a Survey of Current Practices for Sampling of Nervous System in Rodents and Non-rodents in General Toxicity Studies

    EPA Science Inventory

    A survey of current practices for sampling and examination of the nervous system in rodents and non-rodents for general and neurotoxicity (NT) studies was conducted by the Nervous System Sampling Subcommittee of the STP. For general toxicity studies most of those surveyed (>63%) ...

  15. Forest rodents provide directed dispersal of Jeffrey pine seeds

    USGS Publications Warehouse

    Briggs, J.S.; Wall, S.B.V.; Jenkins, S.H.

    2009-01-01

    Some species of animals provide directed dispersal of plant seeds by transporting them nonrandomly to microsites where their chances of producing healthy seedlings are enhanced. We investigated whether this mutualistic interaction occurs between granivorous rodents and Jeffrey pine (Pinus Jeffreyi) in the eastern Sierra Nevada by comparing the effectiveness of random abiotic seed dispersal with the dispersal performed by four species of rodents: deer mice (Peromyscus maniculatus), yellow-pine and long-eared chipmunks (Tamias amoenus and T. quadrimaculatus), and golden-mantled ground squirrels (Spermophilus lateralis). We conducted two caching studies using radio-labeled seeds, the first with individual animals in field enclosures and the second with a community of rodents in open forest. We used artificial caches to compare the fates of seeds placed at the range of microsites and depths used by animals with the fates of seeds dispersed abiotically. Finally, we examined the distribution and survival of naturally establishing seedlings over an eight-year period. Several lines of evidence suggested that this community of rodents provided directed dispersal. Animals preferred to cache seeds in microsites that were favorable for emergence or survival of seedlings and avoided caching in microsites in which seedlings fared worst. Seeds buried at depths typical of animal caches (5-25 mm) produced at least five times more seedlings than did seeds on the forest floor. The four species of rodents differed in the quality of dispersal they provided. Small, shallow caches made by deer mice most resembled seeds dispersed by abiotic processes, whereas many of the large caches made by ground squirrels were buried too deeply for successful emergence of seedlings. Chipmunks made the greatest number of caches within the range of depths and microsites favorable for establishment of pine seedlings. Directed dispersal is an important element of the population dynamics of Jeffrey pine, a dominant tree species in the eastern Sierra Nevada. Quantifying the occurrence and dynamics of directed dispersal in this and other cases will contribute to better understanding of mutualistic coevolution of plants and animals and to more effective management of ecosystems in which directed dispersal is a keystone process. ?? 2009 by the Ecological society of America.

  16. Transitions between Andean and Amazonian centers of endemism in the radiation of some arboreal rodents

    PubMed Central

    2013-01-01

    Background The tropical Andes and Amazon are among the richest regions of endemism for mammals, and each has given rise to extensive in situ radiations. Various animal lineages have radiated ex situ after colonizing one of these regions from the other: Amazonian clades of dendrobatid frogs and passerine birds may have Andean ancestry, and transitions from the Amazon to Andes may be even more common. To examine biogeographic transitions between these regions, we investigated the evolutionary history of three clades of rodents in the family Echimyidae: bamboo rats (Dactylomys-Olallamys-Kannabateomys), spiny tree-rats (Mesomys-Lonchothrix), and brush-tailed rats (Isothrix). Each clade is distributed in both the Andes and Amazonia, and is more diverse in the lowlands. We used two mitochondrial (cyt-b and 12S) and three nuclear (GHR, vWF, and RAG1) markers to reconstruct their phylogenetic relationships. Tree topologies and ancestral geographic ranges were then used to determine whether Andean forms were basal to or derived from lowland radiations. Results Four biogeographic transitions are identified among the generic radiations. The bamboo rat clade unambiguously originated in the Amazon ca. 9Ma, followed by either one early transition to the Andes (Olallamys) and a later move to the Amazon (Dactylomys), or two later shifts to the Andes (one in each genus). The Andean species of both Dactylomys and Isothrix are sister to their lowland species, raising the possibility that highland forms colonized the Amazon Basin. However, uncertainty in their reconstructed ancestral ranges obscures the origin of these transitions. The lone Andean species of Mesomys is confidently nested within the lowland radiation, thereby indicating an Amazon-to-Andes transition ca. 2Ma. Conclusions Differences in the timing of these biogeographic transitions do not appear to explain the different polarities of these trees. Instead, even within the radiation of a single family, both Andean and Amazonian centers of endemism appear enriched by lineages that originated in the other region. Our survey of other South American lineages suggests a pattern of reciprocal exchange between these regionsamong mammals, birds, amphibians, and insects we found no fewer than 87 transitions between the Andes and Amazon from Miocene-Pleistocene. Because no clear trend emerges between the timing and polarity of transitions, or in their relative frequency, we suggest that reciprocal exchange between tropical highland and lowland faunas in South America has been a continual process since ca. 12Ma. PMID:24015814

  17. Tropical Cyclogenesis in a Tropical Wave Critical Layer: Easterly Waves

    NASA Technical Reports Server (NTRS)

    Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

    2009-01-01

    The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside.

  18. Heating rates in tropical anvils

    NASA Technical Reports Server (NTRS)

    Ackerman, Thomas P.; Valero, Francisco P. J.; Pfister, Leonhard; Liou, Kuo-Nan

    1988-01-01

    The interaction of infrared and solar radiation with tropical cirrus anvils is addressed. Optical properties of the anvils are inferred from satellite observations and from high-altitude aircraft measurements. An infrared multiple-scattering model is used to compute heating rates in tropical anvils. Layer-average heating rates in 2 km thick anvils were found to be on the order of 20 to 30 K/day. The difference between heating rates at cloud bottom and cloud top ranges from 30 to 200 K/day, leading to convective instability in the anvil. The calculations are most sensitive to the assumed ice water content, but also are affected by the vertical distribution of ice water content and by the anvil thickness. Solar heating in anvils is shown to be less important than infrared heating but not negligible. The dynamical implications of the computed heating rates are also explored and it is concluded that the heating may have important consequences for upward mass transport in the tropics. The potential impact of tropical cirrus on the tropical energy balance and cloud forcing are discussed.

  19. Past glaciation in the tropics

    NASA Astrophysics Data System (ADS)

    Hastenrath, Stefan

    2009-05-01

    Tropical glaciers are considered along three meridional profiles, for the Australasian sector, Africa and the Americas. Evaluated are the annual mean freezing level 0 C, modern equilibrium line altitude MEL, and past equilibrium line altitude PEL. The calculation of 0 C is based on a 1958-1997 global data set; MEL refers to estimates concerning the first half of the 20th century; and the timing of the PEL is not generally known. 0 C stands around 4000-5000 m, with lower levels in the outer tropics. MEL is reached in the Australasian sector on four mountains, and in Africa on three mountains, near the Equator, near or above 0 C. In the American cordilleras many peaks are still glaciated, above 0 C, but in the arid southern tropical Andes even summits above 6000 m do not reach MEL. The PEL stands between 3000 m and 5000 m, high in the equatorial zone, but highest in the arid southern tropical Andes. The height difference between MEL and PEL is of order 1000 m, with regional differences. Deglaciation dates range between 15,000 and 8000 years BP, with later timing towards the higher elevations. This synopsis suggests priority targets for further research: morphological mapping and age determination in the High Atlas of Morocco; timing of deglaciation in the High Semyen of Ethiopia and the Altos de Cuchumatanes of Guatemala; exploration in the highlands of Lesotho and of the Dominican Republic; and glaciation in the arid southern tropical Andes.

  20. Podoconiosis, a neglected tropical disease.

    PubMed

    Korevaar, D A; Visser, B J

    2012-06-01

    Podoconiosis or 'endemic non-filarial elephantiasis' is a tropical disease caused by exposure of bare feet to irritant alkaline clay soils. This causes an asymmetrical swelling of the feet and lower limbs due to lymphoedema. Podoconiosis has a curable pre-elephantiasic phase. However, once elephantiasis is established, podoconiosis persists and may cause lifelong disability. The disease is associated with living in low-income countries in the tropics in regions with high altitude and high seasonal rainfall. It is found in areas of tropical Africa, Central and South America and north-west India. In endemic areas, podoconiosis is a considerable public health problem. Social stigmatisation of patients is widespread and economic losses are enormous since it mainly affects the most productive people, sustaining the disease-poverty-disease cycle. Podoconiosis is unique in being an entirely preventable, non-communicable tropical disease with the potential for eradication. Low-cost preventive measures are a simple but effective solution. However, so far it has received little attention from health care policy makers and, until recently, research into the disease has been scarce and the pathogenesis and genetic basis are partly unclear. A better understanding of these aspects may lead to new prevention and treatment opportunities. In the past few years, several projects fighting podoconiosis have been started by non-governmental organisations. In February 2011, the World Health Organisation designated podoconiosis as one of the 20 neglected tropical diseases, marking an important step in the fight against the disease. PMID:22744921

  1. Maize, tropical (Zea mays L.).

    PubMed

    Assem, Shireen K

    2015-01-01

    Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines. PMID:25300835

  2. Cross-reactivity of secondary antibodies against African rodents and application for sero-surveillance.

    PubMed

    Nakamura, Ichiro; Hang'ombe, Bernard Mudenda; Sawa, Hirofumi; Kobayashi, Shintaro; Orba, Yasuko; Ishii, Akihiro; Thomas, Yuka; Isozumi, Rie; Yoshimatsu, Kumiko; Mweene, Aaron S; Takada, Ayato; Sugimoto, Chihiro; Arikawa, Jiro

    2013-01-01

    A total of 466 rodents were captured in the Republic of Zambia from 2006 to 2010. Based on morphological observations and phylogenetic analyses of mitochondrial gene sequences, rodents were divided into 10 groups consisting of 39 Rattus rodents, 263 multimammate rats, 18 other Murinae rodents, 95 gerbils, 11 pouched mice, 1 giant-pouched rat, 38 fat mice and 1 dormouse. Rodent antibodies except that from Rattus were examined for their cross-reactivity to commercially available antibody detection reagents. Anti-mouse immunoglobulin G (IgG) was most cross-reactive to heterologous antibodies including multimammate rat, gerbil, pouched mouse and fat mouse. Thus, anti-mouse IgG would be a useful detection tool in serological examination of the Zambian rodent population. Preliminary sero-surveillance for plague, leptospirosis and hantavirus infection was performed by ELISA. PMID:23386359

  3. Mammary gland neoplasia in long-term rodent studies.

    PubMed Central

    Russo, I H; Russo, J

    1996-01-01

    Breast cancer, the most frequent spontaneous malignancy diagnosed in women in the western world, is continuously increasing in incidence in industrialized nations. Although breast cancer develops in women as the result of a combination of external and endogenous factors such as exposure to ionizing radiation, diet, socioeconomic status, and endocrinologic, familial, or genetic factors, no specific etiologic agent(s) or the mechanisms responsible of the disease has been identified as yet. Thus, experimental models that exhibit the same complex interactions are needed for testing various mechanisms and for assessing the carcinogenic potential of given chemicals. Rodent mammary carcinomas represent such a model to a great extent because, in these species, mammary cancer is a multistep complex process that can be induced by either chemicals, radiation, viruses, or genetic factors. Long-term studies in rodent models have been particularly useful for dissecting the initiation, promotion, and progression steps of carcinogenesis. The susceptibility of the rodent mammary gland to develop neoplasms has made this organ a unique target for testing the carcinogenic potential of specific genotoxic chemicals and environmental agents. Mammary tumors induced by indirect- or direct-acting carcinogens such as 7, 12-dimethlbenz(a)anthracene or N-methyl-N-nitrosourea are, in general, hormone dependent adenocarcinomas whose incidence, number of tumors per animal, tumor latency, and tumor type are influenced by the age, reproductive history, and endocarinologic milieu of the host at the time of carcinogen exposure. Rodent models are informative in the absence of human data. They have provided valuable information on the dose and route of administration to be used and optimal host conditions for eliciting maximal tumorigenic response. Studies of the influence of normal gland development on the pathogenesis of chemically induced mammary carcinomas have clarified the role of differentiation in cancer initiation. Comparative studies with the development of the human breast and the pathogenesis of breast cancer have contributed to validate rodent-to-human extrapolations. However, it has not been definitively established what type of information is necessary for human risk assessment, whether currently toxicity testing methodologies are sufficient for fulfilling those needs, or whether treatment-induced tumorigenic responses in rodents are predictive of potential human risk. An alternative to the traditional bioassays are mechanism-based toxicology and molecular and cellular approaches, combined with comparative in vitro systems. These approaches might allow the rapid screen of chemicals for setting priorities for further studies to determine the dose-response relationship for chemical effects at low doses, to assess effects other than mutagenesis and/or tumorigenesis, or to establish qualitative and quantitative relationships of biomarkers to toxic effects. Until there is enough information on the predictive value of mechanism-based toxicology for risk assessment, this approach should be used in conjunction with and validated by the traditional in vivo long-term bioassays. Images Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. A Figure 7. B Figure 8. A Figure 8. B Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. Figure 24. Figure 25. Figure 26. PMID:8899375

  4. Tularemia and plague survey in rodents in an earthquake zone in southeastern Iran

    PubMed Central

    Gyuranecz, Miklós

    2015-01-01

    OBJECTIVES: Earthquakes are one the most common natural disasters that lead to increased mortality and morbidity from transmissible diseases, partially because the rodents displaced by an earthquake can lead to an increased rate of disease transmission. The aim of this study was to evaluate the prevalence of plague and tularemia in rodents in the earthquake zones in southeastern Iran. METHODS: In April 2013, a research team was dispatched to explore the possible presence of diseases in rodents displaced by a recent earthquake magnitude 7.7 around the cities of Khash and Saravan in Sistan and Baluchestan Province. Rodents were trapped near and in the earthquake zone, in a location where an outbreak of tularemia was reported in 2007. Rodent serums were tested for a serological survey using an enzyme-linked immunosorbent assay. RESULTS: In the 13 areas that were studied, nine rodents were caught over a total of 200 trap-days. Forty-eight fleas and 10 ticks were obtained from the rodents. The ticks were from the Hyalomma genus and the fleas were from the Xenopsylla genus. All the trapped rodents were Tatera indica. Serological results were negative for plague, but the serum agglutination test was positive for tularemia in one of the rodents. Tatera indica has never been previously documented to be involved in the transmission of tularemia. CONCLUSIONS: No evidence of the plague cycle was found in the rodents of the area, but evidence was found of tularemia infection in rodents, as demonstrated by a positive serological test for tularemia in one rodent. PMID:26602769

  5. A comparative analysis of parasite species richness of Iberian rodents.

    PubMed

    Feliu, C; Renaud, F; Catzeflis, F; Hugot, J P; Durand, P; Morand, S

    1997-10-01

    Data on parasites of rodents, collected over an 18-year period on the Iberian peninsula, were used to find the determinants of parasite species richness. A total of 77 species of helminth parasites (nematodes, cestodes and digeneans) was identified among 16 species of rodents. Parasites were classified into groups according to their specificity towards their host and their life-cycle. A working phylogeny of the rodents was proposed on the basis of molecular and paleontological data and for each host the following parameters were recorded: sample size, weight, geographical range, longevity, and life-style. Two comparative methods were used, the independent comparisons method of Pagel (1992) and the distance matrix method of Legendre, Lapointe & Casgrain (1995). The second method has the advantage of measuring the relative contribution of phylogeny. Both methods gave similar results. Overall parasite species richness correlated only with host sample size. Host body size does not correlate with any subset of parasite species richness. However, host phylogeny is a good predicator of specific parasites and the species richness of digeneans correlates with host geographical range. A phylogenetic reconstruction of host relations was performed using the parasites belonging to subgroups in which richness is correlated with host phylogeny. These parasite species were treated as Dollo characters, i.e. we made the assumption that the loss of a parasite species is irreversible. The consensus tree obtained reflects the major phylogenetic divisions of the host group. Finally, this study illustrates the relative importance of processes acting at different temporal and spatial scales (evolutionary time and actual geographical range of hosts) in determining the structure of helminth parasite fauna. PMID:9364573

  6. Experimentally induced rodent models of type 2 diabetes.

    PubMed

    Islam, Md Shahidul; Wilson, Rachel Dorothy

    2012-01-01

    Diabetes is one of the major global public health problems and is gradually getting worse particularly in developing nations where 95% of patients are suffering from type 2 diabetes (T2D). Animal models in diabetes research are very common where rodents are the best choice of use due to being smaller in size, easy to handle, omnivorous in nature, and non-wild tranquil behavior. Normally rodent models are classified into two major classes namely: (1) genetic or spontaneously induced models and (2) non-genetic or experimentally induced models. Non-genetic models are more popular compared to genetic models due to lower cost, wider availability, easier to induce diabetes, and of course easier to maintain compared to genetic models. A number of non-genetic models have been developed in last three decades for diabetes research including adult alloxan/streptozotocin (STZ) models, partial pancreatectomy model, high-fat (HF) diet-fed models, fructose-fed models, HF diet-fed STZ models, nicotinamide-STZ models, monosodium-glutamate (MSG) induced models, and intrauterine growth retardation (IUGR) models. A T2D model should have the all major pathogenesis of the disease usually found in humans; however, none of the above-mentioned models are without limitations. This chapter comparatively evaluates most of the experimentally induced rodent models of T2D with their limitations, advantages, disadvantages, and criticality of development in order to help diabetes research groups to more appropriately select the animal models to work on their specific research question. PMID:22893406

  7. Unintentional wildlife poisoning and proposals for sustainable management of rodents.

    PubMed

    Coeurdassier, Michael; Riols, Romain; Decors, Anouk; Mionnet, Aymeric; David, Fabienne; Quintaine, Thomas; Truchetet, Denis; Scheifler, Renaud; Giraudoux, Patrick

    2014-04-01

    In Europe, bromadiolone, an anticoagulant rodenticide authorized for plant protection, may be applied intensively in fields to control rodents. The high level of poisoning of wildlife that follows such treatments over large areas has been frequently reported. In France, bromadiolone has been used to control water voles (Arvicola terrestris) since the 1980s. Both regulation and practices of rodent control have evolved during the last 15 years to restrict the quantity of poisoned bait used by farmers. This has led to a drastic reduction of the number of cases of poisoned wildlife reported by the French surveillance network SAGIR. During the autumn and winter 2011, favorable weather conditions and high vole densities led to the staging of several hundreds of Red Kites (Milvus milvus) in the Puy-de-Dôme department (central France). At the same time, intensive treatments with bromadiolone were performed in this area. Although no misuse has been mentioned by the authorities following controls, 28 Red Kites and 16 Common Buzzards (Buteo buteo) were found dead during surveys in November and December 2011. For all these birds, poisoning by bromadiolone as the main cause of death was either confirmed or highly suspected. Other observations suggest a possible impact of bromadiolone on the breeding population of Red Kites in this area during the spring 2011. French regulation of vole control for plant protection is currently under revision, and we believe this event calls for more sustainable management of rodent outbreaks. Based on large-scale experiments undertaken in eastern France, we propose that direct control of voles at low density (with trapping or limited chemical treatments) and mechanical destruction of vole tunnels, mole control, landscape management, and predator fostering be included in future regulation because such practices could help resolve conservation and agricultural issues. PMID:24405288

  8. APR-2 Tropical Cyclone Observations

    NASA Technical Reports Server (NTRS)

    Durden, S. L.; Tanelli, S.

    2011-01-01

    The Second Generation Airborne Precipitation Radar (APR-2) participated in the Genesis and Rapid Intensification Processes (GRIP) experiment in August and September of 2010, collecting a large volume of data in several tropical systems, including Hurricanes Earl and Karl. Additional measurements of tropical cyclone have been made by APR-2 in experiments prior to GRIP (namely, CAMEX-4, NAMMA, TC4); Table 1 lists all the APR-2 tropical cyclone observations. The APR-2 observations consist of the vertical structure of rain reflectivity at 13.4 and 35.6 GHz, and at both co-polarization and crosspolarization, as well as vertical Doppler measurements and crosswind measurements. APR-2 normally flies on the NASA DC-8 aircraft, as in GRIP, collecting data with a downward looking, cross-track scanning geometry. The scan limits are 25 degrees on either side of the aircraft, resulting in a roughly 10-km swath, depending on the aircraft altitude. Details of the APR-2 observation geometry and performance can be found in Sadowy et al. (2003).The multiparameter nature of the APR-2 measurements makes the collection of tropical cyclone measurements valuable for detailed studies of the processes, microphysics and dynamics of tropical cyclones, as well as weaker systems that are associated with tropical cyclone formation. In this paper, we give a brief overview of how the APR-2 data are processed. We also discuss use of the APR-2 cross-track winds to estimate various quantities of interest in in studies of storm intensification. Finally, we show examples of the standard products and derived information.

  9. Anthocyanins Present in Some Tropical Fruits.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many tropical fruits are rich in anthocyanins, though limited information is available about the characterization and quantification of these anthocyanins. The identification of anthocyanin pigments in four tropical fruits was determined by ion trap mass spectrometry. Fruits studied included acero...

  10. Sexual dimorphism in rodent models of hypertension and atherosclerosis

    PubMed Central

    Bubb, Kristen J; Khambata, Rayomand S; Ahluwalia, Amrita

    2012-01-01

    Approximately one third of all deaths are attributed to cardiovascular disease (CVD), making it the biggest killer worldwide. Despite a number of therapeutic options available, the burden of CVD morbidity continues to grow indicating the need for continued research to address this unmet need. In this respect, investigation of the mechanisms underlying the protection that premenopausal females enjoy from cardiovascular-related disease and mortality is of interest. In this review, we discuss the essential role that rodent animal models play in enabling this field of research. In particular, we focus our discussion on models of hypertension and atherosclerosis. PMID:22582712

  11. Rodent Models and Behavioral Outcomes of Cervical Spinal Cord Injury

    PubMed Central

    Geissler, Sydney A.; Schmidt, Christine E.; Schallert, Timothy

    2014-01-01

    Rodent spinal cord injury (SCI) models have been developed to examine functional and physiological deficits after spinal cord injury with the hope that these models will elucidate information about human SCI. Models are needed to examine possible treatments and to understand histopathology after SCI; however, they should be considered carefully and chosen based on the goals of the study being performed. Contusion, compression, transection, and other models exist and have the potential to reveal important information about SCI that may be related to human SCI and the outcomes of treatment and timing of intervention. PMID:25309824

  12. Mutagenesis in rodents using the L1 retrotransposon

    PubMed Central

    Ostertag, Eric M; Madison, Blair B; Kano, Hiroki

    2007-01-01

    LINE1 (L1) retrotransposons are genetic elements that are present in all mammalian genomes. L1s are active in both humans and mice, and are capable of copying themselves and inserting the copy into a new genomic location. These de novo insertions occasionally result in disease. Endogenous L1 retrotransposons can be modified to increase their activity and mutagenic power in a variety of ways. Here we outline the advantages of using modified L1 retrotransposons for performing random mutagenesis in rodents and discuss several potential applications. PMID:18047693

  13. Pulmonary Toxicity Studies of Lunar Dusts in Rodents

    NASA Technical Reports Server (NTRS)

    Lam, Chiu-wing; James, John T.; Taylor, Larry

    2008-01-01

    NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. NASA established the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Because the toxicity of lunar dust is not known, LADTAG has recommended investigating its toxicity in the lungs of laboratory animals. After receiving this recommendation, NASA directed the JSC Toxicology Laboratory to determine the pulmonary toxicity of lunar dust in exposed rodents. The rodent pulmonary toxicity studies proposed here are the same as those proposed by the LADTAG. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal instillation (ITI). This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. We succeeded in completing an ITI study on JSC-1 lunar dust simulant in mice (Lam et al., Inhalation Toxicology 14:901-916, 2002, and Inhalation Toxicology 14: 917-928, 2002), and have conducted a pilot ITI study to examine the acute toxicity of an Apollo lunar (highland) dust sample. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies have been planned to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The ITI results will also be useful for choosing an exposure concentration for the animal inhalation study on a selected lunar dust sample, which is included as a part of this proposal. The animal inhalation exposure will be conducted with lunar dust simulant prior to the study with the lunar dust. The simulant exposure will ensure that the study techniques used with actual lunar dust will be successful. The results of ITI and inhalation studies will reveal the toxicological risk of exposures and are essential for setting exposure limits on lunar dust for astronauts living in the lunar habitat.

  14. Rodent Habitat On ISS: Spaceflight Effects On Mouse Behavior

    NASA Technical Reports Server (NTRS)

    Ronca, A. E.; Moyer, E. L.; Talyansky, Y.; Padmanabhan, S.; Choi, S.; Gong, C.; Globus, R. K.

    2016-01-01

    The NASA Decadal Survey (2011), Recapturing a Future for Space Exploration: Life and Physical Sciences Research for a New Era, emphasized the importance of expanding NASA life sciences research to long duration, rodent experiments on the International Space Station (ISS). To accomplish this objective, flight hardware, operations, and science capabilities supporting mouse studies in space were developed at NASA Ames Research Center. The first flight experiment carrying mice, Rodent Research Hardware and Operations Validation (Rodent Research-1), was launched on Sept 21, 2014 in an unmanned Dragon Capsule, SpaceX4, exposing the mice to a total of 37 days in space. Ground control groups were maintained in environmental chambers at Kennedy Space Center. Mouse health and behavior were monitored for the duration of the experiment via video streaming. Here we present behavioral analysis of two groups of five C57BL/6 female adult mice viewed via fixed camera views compared with identically housed Ground Controls. Flight (Flt) and Ground Control (GC) mice exhibited the same range of behaviors, including eating, drinking, exploratory behavior, self- and allo-grooming, and social interactions at similar or greater levels of occurrence. Mice propelled themselves freely and actively throughout the Habitat using their forelimbs to push off or by floating from one cage area to another, and they quickly learned to anchor themselves using tails and/or paws. Overall activity was greater in Flt as compared to GC mice, with spontaneous ambulatory behavior including the development of organized ‘circling’ or ‘race-tracking’ behavior that emerged within the first few days of flight and encompassed the primary dark cycle activity for the remainder of the experiment. We quantified the bout frequency, duration and rate of circling with respect to characteristic behaviors observed in the varying stages of the progressive development of circling: flipping utilizing two sides of the habitat, circling, multi-lap circling and group-circling. Once begun, mice did not regress to flipping behavior or other previous behavioral milestones for the remainder of flight. An overall upward trend in circling frequency, rate, duration, participation, and organization was observed over the course of the 37-day spaceflight experiment. In this presentation, we will summarize qualitative observations and quantitative comparisons of mice in microgravity and 1g conditions. Behavioral analyses provide important insights into the overall health and adaptation of mice to the space environment, and identify unique behaviors and social interactions to guide future habitat development and research on rodents in space.

  15. Regulation of the G2/M Transition in Rodent Oocytes

    PubMed Central

    Downs, Stephen M.

    2014-01-01

    Regulation of maturation in meiotically competent mammalian oocytes is a complex process involving the carefully coordinated exchange of signals between the somatic and germ cell compartments of the ovarian follicle via paracrine and cell-cell coupling pathways. This review highlights recent advances in our understanding of how such signaling controls both meiotic arrest and gonadotropin-triggered meiotic resumption in competent oocytes and relates them to the historical context. Emphasis will be on rodent systems, where many of these new findings have taken place. A regulatory scheme is then proposed that integrates this information into an overall framework for meiotic regulation that demonstrates the complex interplay between different follicular compartments. PMID:20578061

  16. Nonhuman gamblers: lessons from rodents, primates, and robots

    PubMed Central

    Paglieri, Fabio; Addessi, Elsa; De Petrillo, Francesca; Laviola, Giovanni; Mirolli, Marco; Parisi, Domenico; Petrosino, Giancarlo; Ventricelli, Marialba; Zoratto, Francesca; Adriani, Walter

    2014-01-01

    The search for neuronal and psychological underpinnings of pathological gambling in humans would benefit from investigating related phenomena also outside of our species. In this paper, we present a survey of studies in three widely different populations of agents, namely rodents, non-human primates, and robots. Each of these populations offers valuable and complementary insights on the topic, as the literature demonstrates. In addition, we highlight the deep and complex connections between relevant results across these different areas of research (i.e., cognitive and computational neuroscience, neuroethology, cognitive primatology, neuropsychiatry, evolutionary robotics), to make the case for a greater degree of methodological integration in future studies on pathological gambling. PMID:24574984

  17. Nonhuman gamblers: lessons from rodents, primates, and robots.

    PubMed

    Paglieri, Fabio; Addessi, Elsa; De Petrillo, Francesca; Laviola, Giovanni; Mirolli, Marco; Parisi, Domenico; Petrosino, Giancarlo; Ventricelli, Marialba; Zoratto, Francesca; Adriani, Walter

    2014-01-01

    The search for neuronal and psychological underpinnings of pathological gambling in humans would benefit from investigating related phenomena also outside of our species. In this paper, we present a survey of studies in three widely different populations of agents, namely rodents, non-human primates, and robots. Each of these populations offers valuable and complementary insights on the topic, as the literature demonstrates. In addition, we highlight the deep and complex connections between relevant results across these different areas of research (i.e., cognitive and computational neuroscience, neuroethology, cognitive primatology, neuropsychiatry, evolutionary robotics), to make the case for a greater degree of methodological integration in future studies on pathological gambling. PMID:24574984

  18. Glacial climate in the tropics

    SciTech Connect

    Broecker, W.

    1996-06-28

    New findings have caused ideas about the Earth`s climate during the Pleistocene glaciation to change. A consensus seems to be forming that during times of glaciation, climatic conditions in the tropics were quite different from those today. However still to be explained is why strontium-calcium measurements on corals and moble gas measurements of ground water suggest a tropical cooling of 4-6 C while foraminiferal speciation, oxygen isotope, and alkenone results suggest a cooling of no more than 3 C. This article discusses different aspects of the debate. 9 refs., 1 fig.

  19. Multiple Co-infections of Rodents with Hantaviruses, Leptospira, and Babesia in Croatia

    PubMed Central

    Turk, Nenad; Korva, Mia; Margaleti?, Josip; Beck, Relja; Vucelja, Marko; Habu, Josipa; Svoboda, Petra; upanc, Tatjana Avi?; Henttonen, Heikki; Markoti?, Alemka

    2012-01-01

    Abstract Hantaviruses, Leptospira spp., and Babesia spp. are rodent-borne pathogens present worldwide. We studied multiple co-infections of small rodents in Croatia with all three pathogens. Twenty-eight Apodemus flavicollis and 16 Myodes glareolus were tested for the presence of hantavirus RNA by real-time RT-PCR, Leptospira strains by renoculture method and Babesia DNA by PCR. Anti-hantavirus antibodies and anti-Leptospira antibodies were detected by serological methods. Very high infection rates with each pathogen were found in A. flavicollis: 20 of 28 rodents (71%) were infected with Dobrava virus, 13 rodents (46%) were infected with Leptospira, and 5 rodents (18%) were infected with Babesia. Multiple co-infections with all three pathogens were found in 3 of 28 (11%) A. flavicollis animals, suggesting that the same rodent host can be infected with several pathogens at the same time. Dual infections with both hantaviruses and Leptospira were found in 7 of 44 rodents (16%), with hantaviruses and Babesia in 2 rodents (5%), and double infection with both Leptospira and Babesia were found in 1 rodent (2%). Since hantaviruses, Leptospira, and Babesia have similar geographical distributions, it is to be expected that in other parts of the world multiple co-infections, representing a serious threat to public health, can be found. PMID:22217170

  20. Tropical Storm Erin

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Location: The Atlantic Ocean 210 miles south of Galveston, Texas Categorization: Tropical Storm Sustained Winds: 40 mph (60 km/hr)

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Infrared ImageMicrowave Image

    Infrared Images Because infrared radiation does not penetrate through clouds, AIRS infrared images show either the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the storm. In cloud-free areas the AIRS instrument will receive the infrared radiation from the surface of the Earth, resulting in the warmest temperatures (orange/red).

    Microwave Images In the AIRS microwave imagery, deep blue areas in storms show where the most precipitation occurs, or where ice crystals are present in the convective cloud tops. Outside of these storm regions, deep blue areas may also occur over the sea surface due to its low radiation emissivity. On the other hand, land appears much warmer due to its high radiation emissivity.

    Microwave radiation from Earth's surface and lower atmosphere penetrates most clouds to a greater or lesser extent depending upon their water vapor, liquid water and ice content. Precipitation, and ice crystals found at the cloud tops where strong convection is taking place, act as barriers to microwave radiation. Because of this barrier effect, the AIRS microwave sensor detects only the radiation arising at or above their location in the atmospheric column. Where these barriers are not present, the microwave sensor detects radiation arising throughout the air column and down to the surface. Liquid surfaces (oceans, lakes and rivers) have 'low emissivity' (the signal isn't as strong) and their radiation brightness temperature is therefore low. Thus the ocean also appears 'low temperature' in the AIRS microwave images and is assigned the color blue. Therefore deep blue areas in storms show where the most precipitation occurs, or where ice crystals are present in the convective cloud tops. Outside of these storm regions, deep blue areas may also occur over the sea surface due to its low radiation emissivity. Land appears much warmer due to its high radiation emissivity.

    Visible/Near-Infrared Images The AIRS instrument suite contains a sensor that captures radiation in four bands of the visible/near-infrared portion of the electromagetic spectrum. Data from three of these bands are combined to create 'visible' images similar to a snapshot taken with your camera.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  1. Black Swan Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Emanuel, K.; Lin, N.

    2012-12-01

    Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad spectrum of characteristics in our synthetic database, although no large surge has been recorded historically as only one moderate storm passed by the area. Tampa black swans are identified as those that move northward parallel to the west Florida coast with high intensities and resonant with the Florida-shelf edge waves to generate extreme surges up to 10 m in Tampa Bay. The Arabian Sea area has sea surface temperatures warm enough to support the development of severe TCs, but TC development has been limited by low humidity and high wind shear, and only one recorded TC (super cyclonic storm Gonu in 2007) moved close to the Persian Gulf, making landfall in Oman and Iran. Our analysis shows that black swan TCs can originate within the Persian Gulf and make landfall with high intensities in populous places; extreme surges over 9 m for Abu Dubai and Doha and over 7 m for Dubai are possible. Darwin experienced immense devastation from Cyclone Tracy of 1974, but the damage was mainly due to the strong winds (the surge was only about 1.6 m). Our analysis includes extremely intense black swan TCs that make landfall just south of Darwin, generating surges above 10 m; these results may prompt the city to reconsider its TC risk. We are currently analyzing the join probability of the extreme wind and surge of these black swan TCs to more clearly assess their full damage potentials.

  2. Genotoxic evaluation of pirfenidone using erythrocyte rodent micronucleus assay.

    PubMed

    Alcántar-Díaz, Blanca E; Gómez-Meda, Belinda C; Zúñiga-González, Guillermo M; Zamora-Perez, Ana L; González-Cuevas, Jaime; Alvarez-Rodríguez, Bertha A; Sánchez-Parada, María Guadalupe; García-Bañuelos, Jesús J; Armendáriz-Borunda, Juan

    2012-08-01

    Pirfenidone is a non-steroidal antifibrotic compound that has been proposed in clinical protocols and experimental studies as a pharmacological treatment for fibroproliferative diseases. The objective of this study was to determine the genotoxicity or cytotoxicity of three doses of pirfenidone using the micronuclei test in peripheral blood erythrocytes of rodent models. Pirfenidone was administered orally to Balb-C mice for 3 days, and also was administered topically to hairless Sprague Dawley rats during the final stage of gestation. Mice were sampled every 24 h over the course of 6 days; pregnant rats were sampled every 24 h during the last 6 days of gestation, and pups were sampled at birth. Blood smears were analyzed and the frequencies of micronucleated erythrocytes (MNEs), micronucleated polychromatic erythrocytes (MNPCEs), and the proportion of polychromatic erythrocytes (PCEs), were recorded in samples from mice, pregnant rats and rat neonates. Increases in MN frequencies (p<0.03) were noted only in the positive control groups. No genotoxic effects or decreased PCE values were observed neither in newborn rats transplacentally exposed to pirfenidone, or in two adult rodent models when pirfenidone was administered orally or topically. PMID:22683486

  3. Spontaneous and transgenic rodent models of inflammatory bowel disease

    PubMed Central

    Jurjus, Abdo

    2015-01-01

    Inflammatory Bowel Disease (IBD) is a multifactorial disorder with many different putative influences mediating disease onset, severity, progression and diminution. Spontaneous natural IBD is classically expressed as Crohn's Disease (CD) and Ulcerative Colitis (UC) commonly found in primates; lymphoplasmocytic enteritis, eosinophilic gastritis and colitis, and ulcerative colitis with neuronal hyperplasia in dogs; and colitis in horses. Spontaneous inflammatory bowel disease has been noted in a number of rodent models which differ in genetic strain background, induced mutation, microbiota influences and immunopathogenic pathways. Histological lesions in Crohn's Disease feature noncaseating granulomatous inflammation while UC lesions typically exhibit ulceration, lamina propria inflammatory infiltrates and lack of granuloma development. Intestinal inflammation caused by CD and UC is also associated with increased incidence of intestinal neoplasia. Transgenic murine models have determined underlying etiological influences and appropriate therapeutic targets in IBD. This literature review will discuss current opinion and findings in spontaneous IBD, highlight selected transgenic rodent models of IBD and discuss their respective pathogenic mechanisms. It is very important to provide accommodation of induced putative deficits in activities of daily living and to assess discomfort and pain levels in the face of significant morbidity and/or mortality in these models. Epigenetic, environmental (microbiome, metabolome) and nutritional factors are important in IBD pathogenesis, and evaluating ways in which they influence disease expression represent potential investigative approaches with the greatest potential for new discoveries. PMID:26155200

  4. The utility of rodent models of autism spectrum disorders

    PubMed Central

    Lazaro, Maria; Golshani, Peyman

    2015-01-01

    Purpose of Review This review discusses the ways rodent models of autism spectrum disorders (ASDs) have been used to gain critical information convergent molecular pathways, the mechanisms underlying altered microcircuit structure and function, and as a screen for potential cutting edge-treatments. Recent Findings There is convergent evidence that impaired developmental pruning of connections may be a common finding among several mouse models of ASDs. Recent studies have uncovered impaired autophagy by pathological mTOR activation as a potential contributor to microcircuit dysfunction and behavior. ASD related disinhibition and exaggerated synaptic plasticity in multiple distinct circuits in cortex and reward circuits in striatum also contribute to social dysfunction and repetitive behaviors. New exciting molecular therapeutic techniques have reversed cognitive deficits in models of ASD, indicating that mouse models could be used for preclinical translational studies of new treatments. Summary Rodent models of ASDs coupled to new emerging technologies for genome editing, cell-specific functional and structural imaging, and neuronal activity manipulation will yield critical insights into ASD pathogenesis and fuel the emergence of new treatments. PMID:25734952

  5. New Insights from Rodent Models of Fatty Liver Disease

    PubMed Central

    2011-01-01

    Abstract Rodent models of fatty liver disease are essential research tools that provide a window into disease pathogenesis and a testing ground for prevention and treatment. Models come in many varieties involving dietary and genetic manipulations, and sometimes both. High-energy diets that induce obesity do not uniformly cause fatty liver disease; this has prompted close scrutiny of specific macronutrients and nutrient combinations to determine which have the greatest potential for hepatotoxicity. At the same time, diets that do not cause obesity or the metabolic syndrome but do cause severe steatohepatitis have been exploited to study factors important to progressive liver injury, including cell death, oxidative stress, and immune activation. Rodents with a genetic predisposition to overeating offer yet another model in which to explore the evolution of fatty liver disease. In some animals that overeat, steatohepatitis can develop even without resorting to a high-energy diet. Importantly, these models and others have been used to document that aerobic exercise can prevent or reduce fatty liver disease. This review focuses primarily on lessons learned about steatohepatitis from manipulations of diet and eating behavior. Numerous additional insights about hepatic lipid metabolism, which have been gained from genetically engineered mice, are also mentioned. Antioxid. Redox Signal. 15, 535550. PMID:21126212

  6. Axenic isolation of Giardia strains from primates and rodents.

    PubMed

    Majewska, A C; Kasprzak, W

    1990-02-01

    During the examination of animals at the Poznan Zoological Gardens, attempts were made to isolate Giardia strains. Using an in vitro excystation procedure, eight samples of cysts from animals with asymptomatic giardiasis were inoculated on BI-S-33 medium. The ease of isolation and axenization of Giardia was surprising; five axenic isolates of Giardia, belonging to the G. duodenalis morphological group, were established from primates (slow loris, lesser slow loris and siamang) and from rodents (Gambian giant pouched rat and cuis). The growth of all isolates was abundant and similar; the peak number of trophozoites on the seventh day (depending on the Giardia isolate) was 2.3 X 10(6)-3.2 X 10(6) and generation times were 8.2-19.3 h. The easy establishment of these isolates confirmed that they belong to the G. duodenalis morphological group. The recent hypothesis that Giardia may be introduced to a human population from an animal source implies the necessity to isolate and differentiate parasite strains from various hosts. In this respect, the first isolation of Giardia strains from non-human primates and from rodents is of particular importance. PMID:2343527

  7. Management of Rodent Exposure and Allergy in the Pediatric Population

    PubMed Central

    Matsui, Elizabeth C.

    2013-01-01

    Although rodent allergy has long been recognized as an occupational disease, it has only been in the past decade that it has been recognized as a community-based disease that affects children. Most homes in the US have detectable mouse allergen, but the concentrations in inner-city homes are orders of magnitude higher than those found in suburban homes. Home mouse allergen exposure has been linked to sensitization to mouse, and children with asthma who are both sensitized and exposed to high mouse allergen concentrations at home are at greater risk for symptoms, exacerbations and reduced lung function. Rat allergen is found primarily in inner-city homes and has also been linked to asthma morbidity among sensitized children. The objective of this review is to summarize the scientific literature on rodents and their allergens, the effects of exposure to these allergens on allergic respiratory disease, and to make recommendations, based on this evidence base, for the evaluation and management of mouse allergy in the pediatric population. PMID:23912589

  8. Causal evidence between monsoon and evolution of rhizomyine rodents

    NASA Astrophysics Data System (ADS)

    López-Antoñanzas, Raquel; Knoll, Fabien; Wan, Shiming; Flynn, Lawrence J.

    2015-03-01

    The modern Asian monsoonal systems are currently believed to have originated around the end of the Oligocene following a crucial step of uplift of the Tibetan-Himalayan highlands. Although monsoon possibly drove the evolution of many mammal lineages during the Neogene, no evidence thereof has been provided so far. We examined the evolutionary history of a clade of rodents, the Rhizomyinae, in conjunction with our current knowledge of monsoon fluctuations over time. The macroevolutionary dynamics of rhizomyines were analyzed within a well-constrained phylogenetic framework coupled with biogeographic and evolutionary rate studies. The evolutionary novelties developed by these rodents were surveyed in parallel with the fluctuations of the Indian monsoon so as to evaluate synchroneity and postulate causal relationships. We showed the existence of three drops in biodiversity during the evolution of rhizomyines, all of which reflected elevated extinction rates. Our results demonstrated linkage of monsoon variations with the evolution and biogeography of rhizomyines. Paradoxically, the evolution of rhizomyines was accelerated during the phases of weakening of the monsoons, not of strengthening, most probably because at those intervals forest habitats declined, which triggered extinction and progressive specialization toward a burrowing existence.

  9. Spontaneous and transgenic rodent models of inflammatory bowel disease.

    PubMed

    Prattis, Susan; Jurjus, Abdo

    2015-06-01

    Inflammatory Bowel Disease (IBD) is a multifactorial disorder with many different putative influences mediating disease onset, severity, progression and diminution. Spontaneous natural IBD is classically expressed as Crohn's Disease (CD) and Ulcerative Colitis (UC) commonly found in primates; lymphoplasmocytic enteritis, eosinophilic gastritis and colitis, and ulcerative colitis with neuronal hyperplasia in dogs; and colitis in horses. Spontaneous inflammatory bowel disease has been noted in a number of rodent models which differ in genetic strain background, induced mutation, microbiota influences and immunopathogenic pathways. Histological lesions in Crohn's Disease feature noncaseating granulomatous inflammation while UC lesions typically exhibit ulceration, lamina propria inflammatory infiltrates and lack of granuloma development. Intestinal inflammation caused by CD and UC is also associated with increased incidence of intestinal neoplasia. Transgenic murine models have determined underlying etiological influences and appropriate therapeutic targets in IBD. This literature review will discuss current opinion and findings in spontaneous IBD, highlight selected transgenic rodent models of IBD and discuss their respective pathogenic mechanisms. It is very important to provide accommodation of induced putative deficits in activities of daily living and to assess discomfort and pain levels in the face of significant morbidity and/or mortality in these models. Epigenetic, environmental (microbiome, metabolome) and nutritional factors are important in IBD pathogenesis, and evaluating ways in which they influence disease expression represent potential investigative approaches with the greatest potential for new discoveries. PMID:26155200

  10. Causal evidence between monsoon and evolution of rhizomyine rodents.

    PubMed

    Lpez-Antoanzas, Raquel; Knoll, Fabien; Wan, Shiming; Flynn, Lawrence J

    2015-01-01

    The modern Asian monsoonal systems are currently believed to have originated around the end of the Oligocene following a crucial step of uplift of the Tibetan-Himalayan highlands. Although monsoon possibly drove the evolution of many mammal lineages during the Neogene, no evidence thereof has been provided so far. We examined the evolutionary history of a clade of rodents, the Rhizomyinae, in conjunction with our current knowledge of monsoon fluctuations over time. The macroevolutionary dynamics of rhizomyines were analyzed within a well-constrained phylogenetic framework coupled with biogeographic and evolutionary rate studies. The evolutionary novelties developed by these rodents were surveyed in parallel with the fluctuations of the Indian monsoon so as to evaluate synchroneity and postulate causal relationships. We showed the existence of three drops in biodiversity during the evolution of rhizomyines, all of which reflected elevated extinction rates. Our results demonstrated linkage of monsoon variations with the evolution and biogeography of rhizomyines. Paradoxically, the evolution of rhizomyines was accelerated during the phases of weakening of the monsoons, not of strengthening, most probably because at those intervals forest habitats declined, which triggered extinction and progressive specialization toward a burrowing existence. PMID:25759260

  11. Functional Evolution of the Feeding System in Rodents

    PubMed Central

    Cox, Philip G.; Rayfield, Emily J.; Fagan, Michael J.; Herrel, Anthony; Pataky, Todd C.; Jeffery, Nathan

    2012-01-01

    The masticatory musculature of rodents has evolved to enable both gnawing at the incisors and chewing at the molars. In particular, the masseter muscle is highly specialised, having extended anteriorly to originate from the rostrum. All living rodents have achieved this masseteric expansion in one of three ways, known as the sciuromorph, hystricomorph and myomorph conditions. Here, we used finite element analysis (FEA) to investigate the biomechanical implications of these three morphologies, in a squirrel, guinea pig and rat. In particular, we wished to determine whether each of the three morphologies is better adapted for either gnawing or chewing. Results show that squirrels are more efficient at muscle-bite force transmission during incisor gnawing than guinea pigs, and that guinea pigs are more efficient at molar chewing than squirrels. This matches the known diet of nuts and seeds that squirrels gnaw, and of grasses that guinea pigs grind down with their molars. Surprisingly, results also indicate that rats are more efficient as well as more versatile feeders than both the squirrel and guinea pig. There seems to be no compromise in biting efficiency to accommodate the wider range of foodstuffs and the more general feeding behaviour adopted by rats. Our results show that the morphology of the skull and masticatory muscles have allowed squirrels to specialise as gnawers and guinea pigs as chewers, but that rats are high-performance generalists, which helps explain their overwhelming success as a group. PMID:22558427

  12. Chromosomal instability in rodents caused by pollution from Baikonur cosmodrome.

    PubMed

    Kolumbayeva, Saule; Begimbetova, Dinara; Shalakhmetova, Tamara; Saliev, Timur; Lovinskaya, Anna; Zhunusbekova, Benazir

    2014-09-01

    An assessment of the health status of ecosystems exposed to man-made pollution is a vital issue for many countries. Particularly it concerns the consequences of contamination caused by the activity of the space industry. Each rocket launch is accompanied by the introduction of parts of the rocket propellant into the environment. This study aims to scrutinize the effect of the components of rocket fuel on the induction of lipid peroxidation and chromosomal aberrations on rodents inhabiting the area exposed to pollution from Baikonur cosmodrome. The results showed the increase of the level of lipid hydroperoxide and malondialdehyde in the livers of Citellus pygmaeus Pallas and Mus musculus L., which indicates an augmentation of free radical activity and DNA damage. The cytogenetic analysis of bone marrow cells revealed that the frequency of chromosomal aberrations was a few times higher in the rodents from contaminated territory. The signs of oxidative stress and high level of chromosomal aberrations indicate the environmental impact of the cosmodrome, and its possible toxic and mutagenic effects on ecosystems. PMID:24990120

  13. Rodent ultrasonic vocalizations are bound to active sniffing behavior

    PubMed Central

    Sirotin, Yevgeniy B.; Costa, Martín Elias; Laplagne, Diego A.

    2014-01-01

    During rodent active behavior, multiple orofacial sensorimotor behaviors, including sniffing and whisking, display rhythmicity in the theta range (~5–10 Hz). During specific behaviors, these rhythmic patterns interlock, such that execution of individual motor programs becomes dependent on the state of the others. Here we performed simultaneous recordings of the respiratory cycle and ultrasonic vocalization emission by adult rats and mice in social settings. We used automated analysis to examine the relationship between breathing patterns and vocalization over long time periods. Rat ultrasonic vocalizations (USVs, “50 kHz”) were emitted within stretches of active sniffing (5–10 Hz) and were largely absent during periods of passive breathing (1–4 Hz). Because ultrasound was tightly linked to the exhalation phase, the sniffing cycle segmented vocal production into discrete calls and imposed its theta rhythmicity on their timing. In turn, calls briefly prolonged exhalations, causing an immediate drop in sniffing rate. Similar results were obtained in mice. Our results show that ultrasonic vocalizations are an integral part of the rhythmic orofacial behavioral ensemble. This complex behavioral program is thus involved not only in active sensing but also in the temporal structuring of social communication signals. Many other social signals of mammals, including monkey calls and human speech, show structure in the theta range. Our work points to a mechanism for such structuring in rodent ultrasonic vocalizations. PMID:25477796

  14. Chemotherapy-Induced Peripheral Neuropathic Pain and Rodent Models.

    PubMed

    Hama, Aldric; Takamatsu, Hiroyuki

    2016-01-01

    Painful peripheral neuropathies resulting from cancer chemotherapy treatment is frequently dose-dependent and may diminish following dose reduction or termination of chemotherapy. However, dose reduction or treatment termination could lead to reemergence of the cancer. In addition, chemotherapy-induced peripheral neuropathy (CIPN) may persist long after termination of chemotherapy. Thus, there is a need for treatments to ameliorate pain during the course of an effective cancer treatment regimen. Because the mechanism underlying CIPN has yet to be fully characterized, there is a current lack of effective treatments for CIPN. Preclinical studies in CIPN rodent models have suggested a number of potential neuropathological mechanisms, which could serve as platforms for the development of novel therapeutics. Although a number of potential analgesic therapies have demonstrated robust efficacy in preclinical studies, rigorous clinical testing has yet to fully validate the preclinical findings. The lack of congruence between preclinical and clinical findings could be in part due to the phylogenetic distance between the main model species and humans. Thus, a CIPN model in nonhuman primates could serve to bridge the translational gap between laboratory findings in small animals and clinical utility. The current review points out the short comings of current CIPN rodent models and suggests the use of large animals, such as the nonhuman primate, to narrow the translational gap between preclinical and clinical findings and the discovery of novel therapeutics. PMID:26553161

  15. Molecular detection of bacterial contamination in gnotobiotic rodent units

    PubMed Central

    Packey, Christopher D; Shanahan, Michael T; Manick, Sayeed; Bower, Maureen A; Ellermann, Melissa; Tonkonogy, Susan L; Carroll, Ian M; Sartor, R Balfour

    2013-01-01

    Gnotobiotic rodents provide an important technique to study the functional roles of commensal bacteria in host physiology and pathophysiology. To ensure sterility, these animals must be screened frequently for contamination. The traditional screening approaches of culturing and Gram staining feces have inherent limitations, as many bacteria are uncultivable and fecal Gram stains are difficult to interpret. Thus, we developed and validated molecular methods to definitively detect and identify contamination in germ-free (GF) and selectively colonized animals. Fresh fecal pellets were collected from rodents housed in GF isolators, spontaneously contaminated ex-GF isolators, selectively colonized isolators and specific pathogen-free (SPF) conditions. DNA isolated from mouse and rat fecal samples was amplified by polymerase chain reaction (PCR) and subjected to quantitative PCR (qPCR) using universal primers that amplify the 16S rRNA gene from all bacterial groups. PCR products were sequenced to identify contaminating bacterial species. Random amplification of polymorphic DNA (RAPD) PCR profiles verified bacterial inoculation of selectively colonized animals. These PCR techniques more accurately detected and identified GF isolator contamination than current standard approaches. These molecular techniques can be utilized to more definitively screen GF and selectively colonized animals for bacterial contamination when Gram stain and/or culture results are un-interpretable or inconsistent. PMID:23887190

  16. Holocene vegetation history from fossil rodent middens near Arequipa, Peru

    USGS Publications Warehouse

    Holmgren, C.A.; Betancourt, J.L.; Rylander, K.A.; Roque, J.; Tovar, O.; Zeballos, H.; Linares, E.; Quade, Jay

    2001-01-01

    Rodent (Abrocoma, Lagidium, Phyllotis) middens collected from 2350 to 2750 m elevation near Arequipa, Peru (16??S), provide an ???9600-yr vegetation history of the northern Atacama Desert, based on identification of >50 species of plant macrofossils. These midden floras show considerable stability throughout the Holocene, with slightly more mesophytic plant assemblages in the middle Holocene. Unlike the southwestern United States, rodent middens of mid-Holocene age are common. In the Arequipa area, the midden record does not reflect any effects of a mid-Holocene mega drought proposed from the extreme lowstand (100 m below modern levels, >6000 to 3500 yr B.P.) of Lake Titicaca, only 200 km east of Arequipa. This is perhaps not surprising, given other evidence for wetter summers on the Pacific slope of the Andes during the middle Holocene as well as the poor correlation of summer rainfall among modern weather stations in the central AndesAtacama Desert. The apparent difference in paleoclimatic reconstructions suggests that it is premature to relate changes observed during the Holocene to changes in El Nin??o Southern Oscillation modes. ?? 2001 University of Washington.

  17. Population Ecology of Hantavirus Rodent Hosts in Southern Brazil

    PubMed Central

    Teixeira, Bernardo R.; Loureiro, Nathalie; Strecht, Liana; Gentile, Rosana; Oliveira, Renata C.; Guterres, Alexandro; Fernandes, Jorlan; Mattos, Luciana H. B. V.; Raboni, Sonia M.; Rubio, Giselia; Bonvicino, Cibele R.; Duarte dos Santos, Claudia N.; Lemos, Elba R. S.; D'Andrea, Paulo S.

    2014-01-01

    In this study we analyze population dynamics of hantavirus rodent hosts and prevalence of infection over a 2-year period in Southern Brazil, a region with a high incidence of hantavirus pulmonary syndrome. The 14 small mammal species captured were composed of 10 rodents and four marsupials, the six most abundant species being Akodon serrensis, Oxymycterus judex, Akodon montensis, Akodon paranaensis, Oligoryzomys nigripes, and Thaptomys nigrita. These species displayed a similar pattern with increasing population sizes in fall/winter caused by recruitment and both, increase in reproductive activity and higher hantavirus prevalence in spring/summer. Specific associations between A. montensis/Jabor Virus (JABV) and O. nigripes/Juquitiba-like Virus (JUQV-like) and spillover infections between A. paranaensis/JABV, A. serrensis/JABV, and A. paranaensis/JUQV-like were observed. Spillover infection in secondary hosts seems to play an important role in maintaining JABV and JUQV-like in the hantavirus sylvatic cycle mainly during periods of low prevalence in primary hosts. PMID:24935954

  18. The Need for Speed in Rodent Locomotion Analyses

    PubMed Central

    Batka, Richard J.; Brown, Todd J.; Mcmillan, Kathryn P.; Meadows, Rena M.; Jones, Kathryn J.; Haulcomb, Melissa M.

    2016-01-01

    Locomotion analysis is now widely used across many animal species to understand the motor defects in disease, functional recovery following neural injury, and the effectiveness of various treatments. More recently, rodent locomotion analysis has become an increasingly popular method in a diverse range of research. Speed is an inseparable aspect of locomotion that is still not fully understood, and its effects are often not properly incorporated while analyzing data. In this hybrid manuscript, we accomplish three things: (1) review the interaction between speed and locomotion variables in rodent studies, (2) comprehensively analyze the relationship between speed and 162 locomotion variables in a group of 16 wild-type mice using the CatWalk gait analysis system, and (3) develop and test a statistical method in which locomotion variables are analyzed and reported in the context of speed. Notable results include the following: (1) over 90% of variables, reported by CatWalk, were dependent on speed with an average R2 value of 0.624, (2) most variables were related to speed in a nonlinear manner, (3) current methods of controlling for speed are insufficient, and (4) the linear mixed model is an appropriate and effective statistical method for locomotion analyses that is inclusive of speed-dependent relationships. Given the pervasive dependency of locomotion variables on speed, we maintain that valid conclusions from locomotion analyses cannot be made unless they are analyzed and reported within the context of speed. PMID:24890845

  19. Causal evidence between monsoon and evolution of rhizomyine rodents

    PubMed Central

    López-Antoñanzas, Raquel; Knoll, Fabien; Wan, Shiming; Flynn, Lawrence J.

    2015-01-01

    The modern Asian monsoonal systems are currently believed to have originated around the end of the Oligocene following a crucial step of uplift of the Tibetan-Himalayan highlands. Although monsoon possibly drove the evolution of many mammal lineages during the Neogene, no evidence thereof has been provided so far. We examined the evolutionary history of a clade of rodents, the Rhizomyinae, in conjunction with our current knowledge of monsoon fluctuations over time. The macroevolutionary dynamics of rhizomyines were analyzed within a well-constrained phylogenetic framework coupled with biogeographic and evolutionary rate studies. The evolutionary novelties developed by these rodents were surveyed in parallel with the fluctuations of the Indian monsoon so as to evaluate synchroneity and postulate causal relationships. We showed the existence of three drops in biodiversity during the evolution of rhizomyines, all of which reflected elevated extinction rates. Our results demonstrated linkage of monsoon variations with the evolution and biogeography of rhizomyines. Paradoxically, the evolution of rhizomyines was accelerated during the phases of weakening of the monsoons, not of strengthening, most probably because at those intervals forest habitats declined, which triggered extinction and progressive specialization toward a burrowing existence. PMID:25759260

  20. Visual landmarks facilitate rodent spatial navigation in virtual reality environments

    PubMed Central

    Youngstrom, Isaac A.; Strowbridge, Ben W.

    2012-01-01

    Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain areas. Virtual reality offers a unique approach to ask whether visual landmark cues alone are sufficient to improve performance in a spatial task. We found that mice could learn to navigate between two water reward locations along a virtual bidirectional linear track using a spherical treadmill. Mice exposed to a virtual environment with vivid visual cues rendered on a single monitor increased their performance over a 3-d training regimen. Training significantly increased the percentage of time avatars controlled by the mice spent near reward locations in probe trials without water rewards. Neither improvement during training or spatial learning for reward locations occurred with mice operating a virtual environment without vivid landmarks or with mice deprived of all visual feedback. Mice operating the vivid environment developed stereotyped avatar turning behaviors when alternating between reward zones that were positively correlated with their performance on the probe trial. These results suggest that mice are able to learn to navigate to specific locations using only visual cues presented within a virtual environment rendered on a single computer monitor. PMID:22345484

  1. Midlatitude tropical interactions during winter

    NASA Technical Reports Server (NTRS)

    Chang, C. P.

    1985-01-01

    Pre-FGGE and FGGE/MONEX data are used to identify short term midlatitude tropical and longitudinal interactions during the winter monsoon. These interactions occur as cold surges, which develop over the East Asian continent and penetrate deep into the tropics with fast gravity wave speed. The observed interactions that occur after a surge include cyclogenesis and enhanced convection in the equatorial region, feedback from equatorial convection to midlatitude circulation systems, tropical east-west (Walker) circulations, and cross-equatorial influence. These interactions are also studied theoretically by analytical solutions of linearized shallow water equations. Response to transient forcing (monsoon surges) are mainly in Rossby and Kelvin modes. When the forcing time scale is short, significant gravity modes are also excited. The responses closely resemble observed winter monsoon flow. Responses to stationary forcing show that deep (barotropic) motions propagate energy away into high latitudes and that shallow (baroclinic) motions are trapped around the equator. It is shown that the barotropic teleconnection-type response to tropical sources found in previous numerical studies was due to the specified vertical wind shear and surface friction.

  2. Intensity of prehistoric tropical cyclones

    NASA Astrophysics Data System (ADS)

    Nott, Jonathan F.

    2003-04-01

    Prediction of future tropical cyclone climate scenarios requires identification of quasi-periodicities at a variety of temporal scales. Extension of records to identify trends at century and millennial scales is important, but to date the emerging field of paleotempestology has been hindered by the lack of a suitable methodology to discern the intensity of prehistoric storms. Here a technique to quantify the central pressure of prehistoric tropical cyclones is presented in detail and demonstrated for the tropical southwest Pacific region. The importance of extending records to century time scales is highlighted for northeast Australia, where a virtual absence of category 5 cyclones during the 20th century stands in contrast to an active period of severe cyclogenesis during the previous century. Several land crossing storms during the 19th century achieved central pressures lower than that ever recorded historically and close to the theoretical thermodynamic limit of storms for the region. This technique can be applied to all tropical and subtropical regions globally and will assist in obtaining more realistic predictions for future storm scenarios with implications for insurance premiums, urban and infrastructural design, and emergency planning.

  3. Tropical Biological Drawings with Notes.

    ERIC Educational Resources Information Center

    Mitchelmore, June A.

    The annotated illustrations of biological specimens useful for illustrating the "tropical" topics dealt with in African secondary school biology courses are designed to serve a two-fold purpose. The diagrams are intended to show the pupil the structures he should be looking for in his laboratory work, with the textual material being an addition to

  4. Tropical Biological Drawings with Notes.

    ERIC Educational Resources Information Center

    Mitchelmore, June A.

    The annotated illustrations of biological specimens useful for illustrating the "tropical" topics dealt with in African secondary school biology courses are designed to serve a two-fold purpose. The diagrams are intended to show the pupil the structures he should be looking for in his laboratory work, with the textual material being an addition to…

  5. Skin Diseases in the Tropics.

    ERIC Educational Resources Information Center

    Mahe, Antoine; And Others

    1994-01-01

    Common skin diseases are prevalent in tropical countries because of extreme weather conditions, mediocre hygiene, and lack of adequate treatment of infectious dermatoses. This guide describes the major endemic skin diseases and their signs for the purpose of helping unspecialized health agents train themselves and determine when a patient should…

  6. The future of tropical forests.

    PubMed

    Wright, S Joseph

    2010-05-01

    Five anthropogenic drivers--land use change, wood extraction, hunting, atmospheric change, climate change--will largely determine the future of tropical forests. The geographic scope and intensity of these five drivers are in flux. Contemporary land use change includes deforestation (approximately 64,000 km(2) yr(-1) for the entire tropical forest biome) and natural forests regenerating on abandoned land (approximately 21,500 km(2) yr(-1) with just 29% of the biome evaluated). Commercial logging is shifting rapidly from Southeast Asia to Africa and South America, but local fuelwood consumption continues to constitute 71% of all wood production. Pantropical rates of net deforestation are declining even as secondary and logged forests increasingly replace old-growth forests. Hunters reduce frugivore, granivore and browser abundances in most forests. This alters seed dispersal, seed and seedling survival, and hence the species composition and spatial template of plant regeneration. Tropical governments have responded to these local threats by protecting 7% of all land for the strict conservation of nature--a commitment that is only matched poleward of 40 degrees S and 70 degrees N. Protected status often fails to stop hunters and is impotent against atmospheric and climate change. There are increasing reports of stark changes in the structure and dynamics of protected tropical forests. Four broad classes of mechanisms might contribute to these changes. Predictions are developed to distinguish among these mechanisms. PMID:20536814

  7. Ecology and management of rodents in no-till agriculture in Washington, USA.

    PubMed

    Witmer, Gary; Sayler, Rodney; Huggins, David; Capelli, Jason

    2007-09-01

    No-till farming is an important approach to sustainable agriculture because it can conserve soil and water resources. Unfortunately, rodent populations can thrive under no-till conditions because burrow systems are not disrupted by annual plowing and plant residues build-up on the surface, providing cover and insulation. This can result in substantial crop damage. We assessed rodent populations, habitat use, food habits, and crop damage in a no-till cropping system in Washington, USA. We also conducted preliminary trials of methods to reduce rodent populations and crop damage. In the fall, many more rodents were captured in fields with unharvested crops than in fields containing only plant stubble, suggesting that rodents leave fields after crop harvest, providing that suitable habitats are nearby, even when adequate cover is still available in harvested crop fields. By spring, the number of voles captured was much lower relative to fall. Despite this, capture rates were much higher in surrounding permanent grass areas than in crop (barley, wheat, pea) fields, suggesting that these grassy areas serve as refugia for rodents. Furthermore, the permanent grass cover type was the landscape variable most associated with rodent capture rates. In three winter pea fields, rodents removed 5-15% of the pea plants over winter. Examination of stomach contents revealed that voles mainly fed on grain plants in spring, but that their diet was more diversified in fall. Deer mice fed heavily on grain plants in both spring and fall, but also used insects as food. Metal barrier exclosures (9 m 9 m), extending above and below ground, did not prevent access by rodents. Rodent populations in areas treated with zinc phosphide on grain were comparable to untreated areas 1 year after application of the rodenticide, perhaps because of immigration and recruitment, suggesting that baiting does not provide a long-term solution to rodent damage in no-till agricultural fields. PMID:21396031

  8. Tropical cyclogenesis in a tropical wave critical layer: easterly waves

    NASA Astrophysics Data System (ADS)

    Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

    2008-06-01

    The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, resembles the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development within the critical layer is given by the intersection of the wave's critical latitude and trough axis, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally this "marsupial paradigm" one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. This translation requires an appropriate "gauge" that renders translating streamlines and isopleths of translating stream function approximately equivalent to flow trajectories. In the translating frame, the closed circulation is stationary, and a dividing streamline effectively separates air within the critical layer from air outside. The critical layer equatorward of the easterly jet axis is important to tropical cyclogenesis because it provides (i) a region of cyclonic vorticity and weak deformation by the resolved flow, (ii) containment of moisture entrained by the gyre and/or lofted by deep convection therein, (iii) confinement of mesoscale vortex aggregation, (iv) a predominantly convective type of heating profile, and (v) maintenance or enhancement of the parent wave until the vortex becomes a self-sustaining entity and emerges from the wave as a tropical depression. These ideas are formulated in three new hypotheses describing the flow kinematics and dynamics, moist thermodynamics and wave/vortex interactions comprising the marsupial paradigm. A survey of 55 named tropical storms in 1998-2001 reveals that actual critical layers sometimes resemble the ideal east-west train of cat's eyes, but are usually less regular, with one or more recirculation regions in the translating frame. It is shown that a "wave gauge" given by the translation speed of the parent wave is the appropriate choice, as well, for isolated proto-vortices carried by the wave. Some implications for entrainment/containment of vorticity and moisture in the cat's eye are discussed from this perspective, based on the observational survey.

  9. Tropical cyclogenesis in a tropical wave critical layer: easterly waves

    NASA Astrophysics Data System (ADS)

    Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

    2009-08-01

    The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside. The critical layer equatorward of the easterly jet axis is important to tropical cyclogenesis because its cat's eye provides (i) a region of cyclonic vorticity and weak deformation by the resolved flow, (ii) containment of moisture entrained by the developing gyre and/or lofted by deep convection therein, (iii) confinement of mesoscale vortex aggregation, (iv) a predominantly convective type of heating profile, and (v) maintenance or enhancement of the parent wave until the vortex becomes a self-sustaining entity and emerges from the wave as a tropical depression. The entire sequence is likened to the development of a marsupial infant in its mother's pouch. These ideas are formulated in three new hypotheses describing the flow kinematics and dynamics, moist thermodynamics and wave/vortex interactions comprising the "marsupial paradigm". A survey of 55 named tropical storms in 1998-2001 reveals that actual critical layers sometimes resemble the ideal east-west train of cat's eyes, but are usually less regular, with one or more recirculation regions in the co-moving frame. It is shown that the kinematics of isolated proto-vortices carried by the wave also can be visualized in a frame of reference translating at or near the phase speed of the parent wave. The proper translation speeds for wave and vortex may vary with height owing to vertical shear and wave-vortex interaction. Some implications for entrainment/containment of vorticity and moisture in the cat's eye are discussed from this perspective, based on the observational survey.

  10. Chern classes of tropical vector bundles

    NASA Astrophysics Data System (ADS)

    Allermann, Lars

    2012-10-01

    We introduce tropical vector bundles, morphisms and rational sections of these bundles and define the pull-back of a tropical vector bundle and of a rational section along a morphism. Most of the definitions presented here for tropical vector bundles will be contained in Torchiani, C., Line Bundles on Tropical Varieties, Diploma thesis, Technische Universitt Kaiserslautern, Kaiserslautern, 2010, for the case of line bundles. Afterwards we use the bounded rational sections of a tropical vector bundle to define the Chern classes of this bundle and prove some basic properties of Chern classes. Finally we give a complete classification of all vector bundles on an elliptic curve up to isomorphisms.

  11. 42 CFR 71.56 - African rodents and other animals that may carry the monkeypox virus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false African rodents and other animals that may carry the monkeypox virus. 71.56 Section 71.56 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES QUARANTINE, INSPECTION, LICENSING FOREIGN QUARANTINE Importations § 71.56 African rodents and other animals that may carry...

  12. Anti-erosion stone bunds influence rodent dynamics and crop damage in Ethiopian highlands

    NASA Astrophysics Data System (ADS)

    Meheretu, Yonas; Welegerima, Kiros; Teferi, Mekonen; Yirga, Gidey; Haile, Mitiku; Sluydts, Vincent; Bauer, Hans; Nyssen, Jan; Deckers, Jozef; Leirs, Herwig

    2014-05-01

    In areas of subsistence agriculture, a variety of soil conservation methods have been implemented in the last few decades to improve crop yields, however these can have unintended consequences such as providing habitat for rodent pests. We studied rodent population dynamics and estimated crop damage in high and low stone bund density fields for four cropping seasons in Tigray highlands, northern Ethiopia. Stone bunds are physical structures for soil and water conservation, and potentially habitat for rodents. We used a general model to relate the proportion of crop damage to rodent abundance, stone bund density and crop stages. We found a positive correlation between rodent abundance and crop damage, and significant variation in rodent abundance and crop damage between high and low stone bund density fields. Furthermore, crop damage also varied significantly between crop stages. We concluded that Mastomys awashensis and Arvicanthis dembeensis were the two most important crop pests in the highlands causing significant damage. Fields with high stone bund density (~10 m average distance apart) harbor more rodents and endure a significantly higher proportion of crop damage compared to fields with lower stone bund density (~15 m average distance apart). The fact that rodent abundances peaked during the reproductive stage of the crop and around harvest implies the need for management intervention before these crop stages are attained.

  13. Molecular Survey of Zoonotic Agents in Rodents and Other Small Mammals in Croatia.

    PubMed

    Tadin, Ante; Tokarz, Rafal; Markotić, Alemka; Margaletić, Josip; Turk, Nenad; Habuš, Josipa; Svoboda, Petra; Vucelja, Marko; Desai, Aaloki; Jain, Komal; Lipkin, W Ian

    2016-02-01

    Croatia is a focus for many rodent-borne zoonosis. Here, we report a survey of 242 rodents and small mammals, including 43 Myodes glareolus, 131 Apodemus flavicollis, 53 Apodemus agrarius, three Apodemus sylvaticus, six Sorex araneus, four Microtus arvalis, one Microtus agrestis, and one Muscardinus avellanarius, collected at eight sites in Croatia over an 8-year period. Multiplex MassTag polymerase chain reaction (PCR) was used for detection of Borrelia, Rickettsia, Bartonella, Babesia, Ehrlichia, Anaplasma, Francisella tularensis, and Coxiella burnetii. Individual PCR assays were used for detection of Leptospira, lymphocytic choriomeningitis virus, orthopoxviruses, flaviviruses, hantaviruses, and Toxoplasma gondii. Of the rodents, 52 (21.5%) were infected with Leptospira, 9 (3.7%) with Borrelia miyamotoi, 5 (2%) with Borrelia afzelii, 29 (12.0%) with Bartonella, 8 (3.3%) with Babesia microti, 2 (0.8%) with Ehrlichia, 4 (1.7%) with Anaplasma, 2 (0.8%) with F. tularensis, 43 (17.8%) with hantaviruses, and 1 (0.4%) with an orthopoxvirus. Other agents were not detected. Multiple infections were found in 32 rodents (13.2%): dual infections in 26 rodents (10.7%), triple infections in four rodents (2.9%), and quadruple infections in two rodents (0.8%). Our findings indicate that rodents in Croatia harbor a wide range of bacteria and viruses that are pathogenic to humans. PMID:26711522

  14. Tick-borne Encephalitis Virus in Wild Rodents in Winter, Finland, 2008–2009

    PubMed Central

    Tonteri, Elina; Tikkakoski, Tapani; Voutilainen, Liina; Niemimaa, Jukka; Henttonen, Heikki; Vaheri, Antti; Vapalahti, Olli

    2011-01-01

    Rodents might maintain tick-borne encephalitis virus (TBEV) in nature through latent persistent infections. During 2 subsequent winters, 2008 and 2009, in Finland, we detected RNA of European and Siberian subtypes of TBEV in Microtus agrestis and Myodes glareolus voles, respectively. Persistence in rodent reservoirs may contribute to virus overwintering. PMID:21192857

  15. Translating Research from Animal Models: Does It Matter that Our Rodents are So Cold?

    EPA Science Inventory

    Does it matter that preclinical rodent models are routinely housed below their thermoneutral zone and are thereby cold-stressed? We compile evidence showing that rodents housed below their thermoneutral zone are cold-stressed, hypermetalbolic, hypertensive, sleep-deprived, obesi...

  16. Teasing Apart the Effects of Seed Size and Energy Content on Rodent Scatter-Hoarding Behavior

    PubMed Central

    Wang, Bo; Yang, Xiaolan

    2014-01-01

    Scatter-hoarding rodents are known to play a crucial role in the seed dispersal of many plant species. Numerous studies have indicated that both seed size and the energy content of seeds can affect rodent foraging behavior. However, seed size is usually associated with energy content per seed, making it difficult to isolate how seed size and energy affect rodent foraging preferences. This study used 99 treatments of artificial seeds (11 seed sizes9 levels of energy content) to tease apart the effect of seed size and energy content on rodent seed-caching behavior. Both seed traits showed significant effects, but their details depended on the stage of the rodent foraging process. Seeds with higher energy content were harvested more rapidly while seed size only had a modest effect on harvest rate. However, after harvesting, seed size showed a much stronger effect on rodent foraging behavior. Rodents choice of which seeds to remove and cache, as well as seed dispersal distance, seemed to reflect an optimal seed size. Our findings could be adapted in future studies to gain a better understanding of scatter-hoarding rodent foraging behavior, and the co-evolutionary dynamics between plant seed production and seed dispersers. PMID:25350369

  17. Estimation of Wildlife Hazard Levels Using Interspecies Correlation Models and Standard Laboratory Rodent Toxicity Data

    EPA Science Inventory

    Toxicity data from laboratory rodents are widely available and frequently used in human health assessments as an animal model. We explore the possibility of using single rodent acute toxicity values to predict chemical toxicity to a diversity of wildlife species and to estimate ...

  18. STUDY OF THE CHEMICAL AND BEHAVIORAL TOXICOLOGY OF SUBSTITUTE CHEMICALS IN MICROTINE RODENTS

    EPA Science Inventory

    Acute oral LD50 and 30-day dietary subacute LC50 studies of 10 selected pesticides were evaluated in microtine rodents. As a means to developing new animal model systems, four species of microtine rodents including Microtus ochrogaster (MO), Microtus canicaudus (MC), Microtus pen...

  19. DEVELOPING A PREDICTIVE SIMULATION MODEL FOR ANTIANDROGEN IMPACTS ON RODENT PROSTATE

    EPA Science Inventory

    Developing a predictive simulation model for antiandrogen impacts on rodent prostate
    HA Barton1, RW Setzer1, LK Potter1,2
    1US EPA, ORD, NHEERL, ETD, PKB, Research Triangle Park, NC and 2Curriculum in Toxicology, UNC, Chapel Hill, NC

    Alterations in rodent prostate wei...

  20. RODENT MANAGEMENT FOR SURFACE DRIP IRRIGATION TUBING IN CORN, COTTON, AND PEANUT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface drip (SD) irrigation of field crops has been gaining interest in the farming community. However, rodent damage is one of the major drawbacks for SD acceptance. This research documents the cost of repairing drip tubing and effectiveness of several rodent control methods. Four sites were used ...

  1. Diversity of gastrointestinal helminths among murid rodents from northern and northeastern Thailand.

    PubMed

    Chaisiri, Kittipong; Chaeychomsri, Win; Siruntawineti, Jindawan; Ribas, Alexis; Herbreteau, Vincent; Morand, Serge

    2012-01-01

    The presence of gastrointestinal helminths (GI helminths) was investigated among 725 murid rodents, trapped in various habitats of Nan, Loei and Buri Ram Provinces, Thailand. The study revealed 17 species of rodents infected with 21 species or taxonomic groups of parasites (3 trematodes, 3 cestodes, 14 nematodes and 1 acanthocephalan). The overall prevalence of infection was 57.7% (418/725). Of the gastrointestinal (GI) helminths, the dominant parasitic group was members of the family Trichostrongylidae (24.3%), followed by the cestodes Raillietina sp (17.1%) and Hymenolepis diminuta (8.6%) and the nematode Syphacia muris (8.6%). The GI helminthic infection rates were highest in Mus caroli (81.8%), Mus cervicolor (76.5%), Leopoldamys edwardsi (75.0%), Bandicota indica (71.5%) and Bandicota savilei (71.4%). Highest rodent species richness (RSR) and helminth species richness (HSR) rates were found in Loei, followed by Nan and Buri Ram. The helminth prevalence rate was higher in rodents from Nan, followed by rodents from Loei and Buri Ram. Rodents from irrigated fields had the highest infection rates followed by rodents from upland or dry agricultural areas, forests and domestic habitats. Raillietina sp, Rodentolepis nana (syn. Hymenolepis nana), Hymenolepis diminuta, Moniliformis moniliformis and Cyclodontostomum purvisi, considered zoonotic parasites, were mainly found in rodents from domestic habitats and lowland irrigated fields. PMID:23082550

  2. Teasing apart the effects of seed size and energy content on rodent scatter-hoarding behavior.

    PubMed

    Wang, Bo; Yang, Xiaolan

    2014-01-01

    Scatter-hoarding rodents are known to play a crucial role in the seed dispersal of many plant species. Numerous studies have indicated that both seed size and the energy content of seeds can affect rodent foraging behavior. However, seed size is usually associated with energy content per seed, making it difficult to isolate how seed size and energy affect rodent foraging preferences. This study used 99 treatments of artificial seeds (11 seed sizes×9 levels of energy content) to tease apart the effect of seed size and energy content on rodent seed-caching behavior. Both seed traits showed significant effects, but their details depended on the stage of the rodent foraging process. Seeds with higher energy content were harvested more rapidly while seed size only had a modest effect on harvest rate. However, after harvesting, seed size showed a much stronger effect on rodent foraging behavior. Rodents' choice of which seeds to remove and cache, as well as seed dispersal distance, seemed to reflect an optimal seed size. Our findings could be adapted in future studies to gain a better understanding of scatter-hoarding rodent foraging behavior, and the co-evolutionary dynamics between plant seed production and seed dispersers. PMID:25350369

  3. Prevalence of SFTSV among Asian house shrews and rodents, China, January-August 2013.

    PubMed

    Liu, Jian-Wei; Wen, Hong-Ling; Fang, Li-Zhu; Zhang, Zhen-Tang; He, Shu-Ting; Xue, Zai-Feng; Ma, Dong-Qiang; Zhang, Xiao-Shuang; Wang, Tao; Yu, Hao; Zhang, Yan; Zhao, Li; Yu, Xue-jie

    2014-12-01

    To evaluate the role of small mammals as hosts of severe fever with thrombocytopenia syndrome virus (SFTSV), we tested serum samples from rodents and shrews in China, collected in 2013. SFTSV antibodies and RNA were detected, suggesting that rodents and shrews might be hosts for SFTSV. PMID:25418111

  4. Rodent repellent studies. IV. Preparation and properties of trinitrobenzene-aryl amine complexes

    USGS Publications Warehouse

    DeWitt, J.B.; Bellack, E.; Welch, J.F.

    1953-01-01

    Data are presented on methods of preparation, chemical arid physical characteristics, toxicity, and repellency to rodents of complexes of symmetrical trinitrohenzene with various aromatic amines: When applied in suitable carriers or incorporated in plastic .films, members of this series ofmaterials were shown to offer significant increases in time required by wild rodents to damage common packaging materials.

  5. Remote tropical and sub-tropical responses to Amazon deforestation

    NASA Astrophysics Data System (ADS)

    Badger, Andrew M.; Dirmeyer, Paul A.

    2015-07-01

    Replacing natural vegetation with realistic tropical crops over the Amazon region in a global Earth system model impacts vertical transport of heat and moisture, modifying the interaction between the atmospheric boundary layer and the free atmosphere. Vertical velocity is decreased over a majority of the Amazon region, shifting the ascending branch and modifying the seasonality of the Hadley circulation over the Atlantic and eastern Pacific oceans. Using a simple model that relates circulation changes to heating anomalies and generalizing the upper-atmosphere temperature response to deforestation, agreement is found between the response in the fully-coupled model and the simple solution. These changes to the large-scale dynamics significantly impact precipitation in several remote regions, namely sub-Saharan Africa, Mexico, the southwestern United States and extratropical South America, suggesting non-local climate repercussions for large-scale land use changes in the tropics are possible.

  6. Cell proliferation not associated with carcinogenesis in rodents and humans.

    PubMed Central

    Ward, J M; Uno, H; Kurata, Y; Weghorst, C M; Jang, J J

    1993-01-01

    Cell proliferation has often been found to be associated with carcinogenesis in rodents and humans at different stages of the multistage carcinogenesis process. The multistage process includes initiation, promotion, and progression phases. At each phase, increasing the normal level of cell turnover of target cells may enhance carcinogenesis. However, we present evidence that normal levels of cell turnover, or increasing the rate of cell turnover at these different stages, do not necessarily lead to enhanced carcinogenesis. In normal tissues, the length of the cell cycle depends on the age of the host and varies from tissue to tissue. Tissues with normal short cell cycles, such as intestine and bone marrow, do not show a high rate of spontaneous tumors in most species. Cells with higher turnover should be more susceptible to carcinogens at the initiation stage of carcinogenesis if cell proliferation per se causes cancer and if these cells or their progeny survive. Cancer in humans is more often associated with specific etiological factors rather than with the natural proliferative rate of specific tissues. For many tissues of humans and rodents, age-related diseases develop in a progressive, irreversible manner. Often, naturally occurring chronic degenerative and inflammatory changes in a tissue (e.g., kidney, liver, heart, reproductive tract) lead to chronic regeneration of the damaged tissue. Yet, cancer is rarely found in these tissues. In rodent carcinogenesis experiments, chronic toxic lesions, accompanied by increases in normal levels of cell turnover, have sometimes been observed in target organs of nongenotoxic carcinogens. More often, however, organ-specific nongenotoxic toxins are not carcinogens. These toxins include compounds toxic for the liver, kidney, and nasal cavity. In 19 inhalation bioassays conducted by the National Toxicology Program, 5/5 nasal carcinogens and 12/14 nasal noncarcinogens caused nasal lesions usually associated with chronic cell proliferation. Although cell proliferation may contribute to multistage carcinogenesis, cell proliferation is not necessarily a tumor promoter or cocarcinogen. Images FIGURE 2. FIGURE 4. FIGURE 5. FIGURE 6. A FIGURE 6. B FIGURE 7. PMID:8013399

  7. In vivo microCT imaging of rodent cerebral vasculature

    PubMed Central

    Seo, Youngho; Hashimoto, Tomoki; Nuki, Yoshitsugu; Hasegawa, Bruce H

    2008-01-01

    Computed tomography (CT) remains a critical diagnostic tool for evaluating patients with cerebrovascular disease, and the advent of specialized systems for imaging rodents has extended these techniques to small animal models of these diseases. We therefore have evaluated in vivo methods of imaging rat models of hemorrhagic stroke using a high resolution compact computed tomography (microCT) system (FLEX(tm) X-O(tm), Gamma Medica-Ideas, Northridge, CA). For all in vivo studies, the head of the anesthetized rat was secured in a custom immobilization device for microCT imaging with 512 projections over 2 min at 60 kVp and 0.530 mA (Itube t/rotation = 63.6 mAs). First, imaging without iodinated contrast was performed (a) to differentiate the effect of contrast agent in contrast-enhanced CT and (b) to examine the effectiveness of the immobilization device between two time points of CT acquisitions. Then, contrast-enhanced CT was performed with continuous administration of iopromide (300 mgI ml?1 at 1.2 ml min?1) to visualize aneurysms and other vascular formations in the carotid and cerebral arteries that may precede subarachnoid hemorrhage. The accuracy of registration between the noncontrast and contrast-enhanced CT images with the immobilization device was compared against the images aligned with normalized mutual information using FMRIB's linear image registration tool (FLIRT). Translations and rotations were examined between the FLIRT-aligned noncontrast CT image and the nonaligned noncontrast CT image. These two data sets demonstrated translational and rotational differences of less than 0.5 voxel (?85 ?m) and 0.5, respectively. Noncontrast CT demonstrated a very small volume (0.1 ml) of femoral arterial blood introduced surgically into the rodent brain. Continuous administration of iopromide during the CT acquisition produced consistent vascular contrast in the reconstructed CT images. As a result, carotid arteries and major cerebral blood vessels were visible with contrast-enhanced CT, but not with noncontrast CT. In conclusion, the CT-compatible immobilization device was useful for in vivo microCT imaging of intracranial blood and of vascular structures within and immediately adjacent to the rodent brain. The microCT imaging technique is also compatible with continuous administration of a conventional iodinated contrast agent (e.g. iopromide) and therefore does not require specialized small animal specific contrast agent that has comparatively long in vivo residence time. PMID:18364539

  8. Coxiella burnetii in Rodents on Heixiazi Island at the Sino-Russian Border

    PubMed Central

    Liu, Lijuan; Baoliang, Xu; Yingqun, Fu; Ming, Li; Yu, Yang; Yong, Hou; Shasha, Wang; Manxia, Hu; Tianyu, Guo; Chao, Jiang; Xiaohong, Sun; Jing, Wang

    2013-01-01

    This work is a molecular epidemiologic study to detect the incidence of Coxiella burnetii in rodents on Heixiazi Island at the Sino-Russian border of Heilongjiang Province. Liver tissues were extracted and processed to test the incidence of C. burnetii infection using polymerase chain reaction analysis. In total, 18% (66 of 370) of rodents tested positive for infection. The results of logistic regression analysis indicated that infection with C. burnetii was associated significantly with weight and month of capture, and infection was found in all rodent species that were observed; there was no significant difference of sex on the infection of C. burnetii. Though phylogenetic analysis disclosed heterogeneity in the nucleotide sequences isolated from the island rodents, the majority of observed strains were among the most common strains found worldwide. This is the first report on the incidence of C. burnetii in rodents on Heixiazi Island at the Sino-Russian border. PMID:23382172

  9. Neurobiology of rodent self-grooming and its value for translational neuroscience.

    PubMed

    Kalueff, Allan V; Stewart, Adam Michael; Song, Cai; Berridge, Kent C; Graybiel, Ann M; Fentress, John C

    2016-01-01

    Self-grooming is a complex innate behaviour with an evolutionarily conserved sequencing pattern and is one of the most frequently performed behavioural activities in rodents. In this Review, we discuss the neurobiology of rodent self-grooming, and we highlight studies of rodent models of neuropsychiatric disorders - including models of autism spectrum disorder and obsessive compulsive disorder - that have assessed self-grooming phenotypes. We suggest that rodent self-grooming may be a useful measure of repetitive behaviour in such models, and therefore of value to translational psychiatry. Assessment of rodent self-grooming may also be useful for understanding the neural circuits that are involved in complex sequential patterns of action. PMID:26675822

  10. Rodents on pig and chicken farms – a potential threat to human and animal health

    PubMed Central

    Backhans, Annette; Fellström, Claes

    2012-01-01

    Rodents can cause major problems through spreading various diseases to animals and humans. The two main species of rodents most commonly found on farms around the world are the house mouse (Mus musculus) and the brown rat (Rattus norvegicus). Both species are omnivorous and can breed year-round under favourable conditions. This review describes the occurrence of pathogens in rodents on specialist pig and chicken farms, which are usually closed units with a high level of bio-security. However, wild rodents may be difficult to exclude completely, even from these sites, and can pose a risk of introducing and spreading pathogens. This article reviews current knowledge regarding rodents as a hazard for spreading disease on farms. Most literature available regards zoonotic pathogens, while the literature regarding pathogens that cause disease in farm animals is more limited. PMID:22957130

  11. Rodents on pig and chicken farms - a potential threat to human and animal health.

    PubMed

    Backhans, Annette; Fellstrm, Claes

    2012-01-01

    Rodents can cause major problems through spreading various diseases to animals and humans. The two main species of rodents most commonly found on farms around the world are the house mouse (Mus musculus) and the brown rat (Rattus norvegicus). Both species are omnivorous and can breed year-round under favourable conditions. This review describes the occurrence of pathogens in rodents on specialist pig and chicken farms, which are usually closed units with a high level of bio-security. However, wild rodents may be difficult to exclude completely, even from these sites, and can pose a risk of introducing and spreading pathogens. This article reviews current knowledge regarding rodents as a hazard for spreading disease on farms. Most literature available regards zoonotic pathogens, while the literature regarding pathogens that cause disease in farm animals is more limited. PMID:22957130

  12. Characterization of novel Brucella strains originating from wild native rodent species in North Queensland, Australia.

    PubMed

    Tiller, Rebekah V; Gee, Jay E; Frace, Michael A; Taylor, Trevor K; Setubal, Joao C; Hoffmaster, Alex R; De, Barun K

    2010-09-01

    We report on the characterization of a group of seven novel Brucella strains isolated in 1964 from three native rodent species in North Queensland, Australia, during a survey of wild animals. The strains were initially reported to be Brucella suis biovar 3 on the basis of microbiological test results. Our results indicated that the rodent strains had microbiological traits distinct from those of B. suis biovar 3 and all other Brucella spp. To reinvestigate these rodent strains, we sequenced the 16S rRNA, recA, and rpoB genes and nine housekeeping genes and also performed multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA). The rodent strains have a unique 16S rRNA gene sequence compared to the sequences of the classical Brucella spp. Sequence analysis of the recA, rpoB, and nine housekeeping genes reveals that the rodent strains are genetically identical to each other at these loci and divergent from any of the currently described Brucella sequence types. However, all seven of the rodent strains do exhibit distinctive allelic MLVA profiles, although none demonstrated an amplicon for VNTR 07, whereas the other Brucella spp. did. Phylogenetic analysis of the MLVA data reveals that the rodent strains form a distinct clade separate from the classical Brucella spp. Furthermore, whole-genome sequence comparison using the maximal unique exact matches index (MUMi) demonstrated a high degree of relatedness of one of the seven rodent Brucella strains (strain NF 2653) to another Australian rodent Brucella strain (strain 83-13). Our findings strongly suggest that this group of Brucella strains isolated from wild Australian rodents defines a new species in the Brucella genus. PMID:20639360

  13. Characterization of Novel Brucella Strains Originating from Wild Native Rodent Species in North Queensland, Australia?

    PubMed Central

    Tiller, Rebekah V.; Gee, Jay E.; Frace, Michael A.; Taylor, Trevor K.; Setubal, Joao C.; Hoffmaster, Alex R.; De, Barun K.

    2010-01-01

    We report on the characterization of a group of seven novel Brucella strains isolated in 1964 from three native rodent species in North Queensland, Australia, during a survey of wild animals. The strains were initially reported to be Brucella suis biovar 3 on the basis of microbiological test results. Our results indicated that the rodent strains had microbiological traits distinct from those of B. suis biovar 3 and all other Brucella spp. To reinvestigate these rodent strains, we sequenced the 16S rRNA, recA, and rpoB genes and nine housekeeping genes and also performed multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA). The rodent strains have a unique 16S rRNA gene sequence compared to the sequences of the classical Brucella spp. Sequence analysis of the recA, rpoB, and nine housekeeping genes reveals that the rodent strains are genetically identical to each other at these loci and divergent from any of the currently described Brucella sequence types. However, all seven of the rodent strains do exhibit distinctive allelic MLVA profiles, although none demonstrated an amplicon for VNTR 07, whereas the other Brucella spp. did. Phylogenetic analysis of the MLVA data reveals that the rodent strains form a distinct clade separate from the classical Brucella spp. Furthermore, whole-genome sequence comparison using the maximal unique exact matches index (MUMi) demonstrated a high degree of relatedness of one of the seven rodent Brucella strains (strain NF 2653) to another Australian rodent Brucella strain (strain 83-13). Our findings strongly suggest that this group of Brucella strains isolated from wild Australian rodents defines a new species in the Brucella genus. PMID:20639360

  14. Effects of Fat and Protein Levels on Foraging Preferences of Tannin in Scatter-Hoarding Rodents

    PubMed Central

    Wang, Bo; Chen, Jin

    2012-01-01

    Both as consumers and dispersers of seeds, scatter-hoarding rodents often play an important role in the reproductive ecology of many plant species. However, the seeds of many plant species contain tannins, which are a diverse group of water-soluble phenolic compounds that have a high affinity for proteins. The amount of tannins in seeds is expected to affect rodent foraging preferences because of their major impact on rodent physiology and survival. However, variable results have been obtained in studies that evaluated the effects of tannin on rodent foraging behavior. Hence, in this study, we aimed to explain these inconsistent results and proposed that a combination of seed traits might be important in rodent foraging behavior, because it is difficult to distinguish between the effects of individual traits on rodent foraging behavior and the interactions among them. By using a novel artificial seed system, we manipulated seed tannin and fat/protein levels to examine directly the univariate effects of each component on the seed preferences of free-ranging forest rats (Apodemus latronum and Apodemus chevrieri) during the behavioral process of scatter hoarding. Our results showed that both tannin and fat/protein had significant effects on rodent foraging behavior. Although only a few interactive effects of tannin and fat/protein were recorded, higher concentrations of both fat and protein could attenuate the exclusion of seeds with higher tannin concentrations by rodents, thus influencing seed fate. Furthermore, aside from the concentrations of tannin, fat, and protein, numerous other traits of plant seeds may also influence rodent foraging behavior. We suggest that by clarifying rodent foraging preferences, a better understanding of the evolution of plant seed traits may be obtained because of their strong potential for selective pressure. PMID:22808217

  15. Ground-based rodent control in a remote Hawaiian rainforest on Maui

    USGS Publications Warehouse

    Malcolm, T.R.; Swinnerton, K.J.; Groombridge, J.J.; Sparklin, B.D.; Brosius, C.N.; Vetter, J.P.; Foster, J.T.

    2008-01-01

    Effective control of introduced mammalian predators is essential to the recovery of native bird species in Hawai'i. Between August 1996 and December 2004, introduced rodents were controlled within three home ranges of the Po'ouli Melamprosops phaeosoma, a critically endangered Hawaiian honeycreeper. Rats were controlled using a combination of ground-based rodenticide (0.005% diphacinone) application and snap traps. Beginning in August 2001, we monitored the effectiveness of these rodent control efforts. Relative abundances of Black Rats Rattus rattus and Polynesian Rats R. exulans were measured in each of five snap-trapping grids seven times over a 35-month period. Rat populations decreased inside of the rodent control areas, but control effectiveness differed between rat species. During the first year of monitoring, target control levels for R. rattus were consistently achieved in only one of the rodent control areas. Control techniques were refined in areas failing to meet targets. Subsequently, we achieved target control levels for R. rattus more consistently in all three rodent control areas. However, relative abundances of R. exulans did not differ between rodent control and reference areas, indicating that our rodent control techniques were insufficient to reduce population levels of this species. These findings signify a need for further improvement of rodent control methods in Hawai'i, especially for Polynesian Rats, and demonstrate the critical importance of periodic monitoring of the response of rodent populations to management. In the future, managers may need to design rodent control operations targeting R. rattus and R. exulans independently to achieve best results.

  16. Rodent and flea abundance fail to predict a plague epizootic in black-tailed prairie dogs.

    PubMed

    Brinkerhoff, Robert Jory; Collinge, Sharon K; Ray, Chris; Gage, Ken L

    2010-01-01

    Small rodents are purported to be enzootic hosts of Yersinia pestis and may serve as sources of infection to prairie dogs or other epizootic hosts by direct or flea-mediated transmission. Recent research has shown that small rodent species composition and small rodent flea assemblages are influenced by the presence of prairie dogs, with higher relative abundance of both small rodents and fleas at prairie dog colony sites compared to grasslands without prairie dogs. However, it is unclear if increased rodent or flea abundance predisposes prairie dogs to infection with Y. pestis. We tracked rodent and flea occurrence for 3 years at a number of prairie dog colony sites in Boulder County, Colorado, before, during, and after a local plague epizootic to see if high rodent or flea abundance was associated with plague-affected colonies when compared to colonies that escaped infection. We found no difference in preepizootic rodent abundance or flea prevalence or abundance between plague-positive and plague-negative colonies. Further, we saw no significant before-plague/after-plague change in these metrics at either plague-positive or plague-negative sites. We did, however, find that small rodent species assemblages changed in the year following prairie dog die-offs at plague-affected colonies when compared to unaffected colonies. In light of previous research from this system that has shown that landscape features and proximity to recently plagued colonies are significant predictors of plague occurrence in prairie dogs, we suggest that landscape context is more important to local plague occurrence than are characteristics of rodent or flea species assemblages. PMID:20158331

  17. Pollen analyses from a 50 000-yr rodent midden series in the southern Atacama Desert (25 300' S)

    USGS Publications Warehouse

    Maldonado, Antonio; Betancourt, Julio L.; Latorre, Claudio; Villagran, Carolina

    2005-01-01

    Precipitation in northern Chile is controlled by two great wind beltsthe southern westerlies over the southern Atacama and points south (>24 S) and the tropical easterlies over the northern and central Atacama Desert (1624 S). At the intersection of these summer and winter rainfall regimes, respectively, is a Mars-like landscape consisting of expansive surfaces devoid of vegetation (i.e. absolute desert) except in canyons that originate high enough to experience runoff once every few years. Pollen assemblages from 39 fossil rodent middens in one of these canyons, Quebrada del Chaco (25 30' S), were used to infer the history of vegetation and precipitation at three elevations (2670800 m; 31003200 m; 34503500 m) over the past 50 000 years. When compared to modern conditions and fossil records to the north and south, the pollen evidence indicates more winter precipitation at >52, 4033, 2417 k cal.yrBP, more precipitation in both seasons at 1714 k cal. yr BP, and more summer precipitation from 1411 k cal. yr BP. Younger middens are scarce at Quebrada del Chaco, and the few Holocene samples indicate hyperarid conditions comparable to today. The only exception is a pollen assemblage that indicates a brief but significant interlude of increased winter precipitation in the last millennium.

  18. Swimming ability in three Costa Rican dry forest rodents.

    PubMed

    Cook, W M; Timm, R M; Hyman, D E

    2001-01-01

    We investigated the swimming abilities of three Costa Rican dry forest rodents (Coues' rice rat. Oryzomys couesi, hispid cotton rat, Sigmodon hispidus, and spiny pocket mouse, Liomys salvini) associated with a large marsh, Laguna Palo Verde, using 90 s swim trials in a plastic container. Swimming ability was evaluated by observing the use of limbs and tail in the water, inclination to the surface, and diving and floating behavior. Rice rats could float, swim and dive, suggesting that they can exploit surface and underwater resources. Cotton rats swam at the water's surface, but were less skilled swimmers than rice rats. Spiny pocket mice tired quickly and had difficulty staying at the water's surface. Results suggest that differential swimming ability is related to the distribution of the three sympatric species within the marsh and adjacent forest habitats. PMID:12189799

  19. Melanocortin Control of Energy Balance: Evidence from Rodent Models

    PubMed Central

    De Jonghe, Bart C.; Hayes, Matthew R.; Bence, Kendra K.

    2011-01-01

    Regulation of energy balance is extremely complex, and involves multiple systems of hormones, neurotransmitters, receptors, and intracellular signals. As data have accumulated over the last two decades, the CNS melanocortin system is now identified as a prominent integrative network of energy balance controls in the mammalian brain. Here, we will review findings from rat and mouse models, which have provided an important framework in which to study melanocortin function. Perhaps most importantly, this review attempts for the first time to summarize recent advances in our understanding of the intracellular signaling pathways thought to mediate the action of melanocortin neurons and peptides in control of long term energy balance. Special attention will be paid to the roles of MC4R/MC3R, as well as downstream neurotransmitters within forebrain and hindbrain structures that illustrate the distributed control of melanocortin signaling in energy balance. In addition, distinctions and controversy between rodent species will be discussed. PMID:21553232

  20. Imaging neuronal population activity in awake and anesthetized rodents.

    PubMed

    Greenberg, David S; Wallace, Damian J; Kerr, Jason N D

    2014-09-01

    Recent advances in in vivo two-photon imaging have extended the technique to permit the detection of action potentials (APs) in populations of spatially resolved neurons in awake animals. Although experimentally demanding, this technique's potential applications include experiments to investigate perception, behavior, and other awake states. Here we outline experimental procedures for imaging neuronal populations in awake and anesthetized rodents. Details are provided on habituation to head fixation, surgery, head plate design, and dye injection. Determination of AP detection accuracy through simultaneous optical and electrophysiological recordings is also discussed. Basic problems of data analysis are considered, such as correction of signal background and baseline drift, AP detection, and motion correction. As an application of the method, the comparison of neuronal activity across arousal states is considered in detail, and some future directions are discussed. PMID:25183826

  1. Endrin versus 12-ketoendrin in birds and rodents

    USGS Publications Warehouse

    Stickel, W.H.; Kaiser, T.E.; Reichel, W.L.

    1979-01-01

    British workers showed that in rats the endrin metabolite, 12-ketoendrin, was five times as toxic as endrin, was probably the ultimate cause of death, and was the main form of endrin in the brain at death. In cows and rabbits, however, they detected little of this metabolite. They found none in hens. We found no 12-ketoendrin in birds of four orders that had been heavily exposed to or killed by endrin. We suggest that residue work with birds need not consider this compound unless birds have been eating endrin-killed rodents. White mice had much less 12-ketoendrin than rats, but had more endrin. In tests with spiked samples, 12-ketoendrin was successfully recovered from extracts by gel permeation chromatography, but not by florisil.

  2. Pathogenesis of depression: Insights from human and rodent studies.

    PubMed

    Ménard, C; Hodes, G E; Russo, S J

    2016-05-01

    Major depressive disorder (MDD) will affect one out of every five people in their lifetime and is the leading cause of disability worldwide. Nevertheless, mechanisms associated with the pathogenesis of MDD have yet to be completely understood and current treatments remain ineffective in a large subset of patients. In this review, we summarize the most recent discoveries and insights for which parallel findings have been obtained in human depressed subjects and rodent models of mood disorders in order to examine the potential etiology of depression. These mechanisms range from synaptic plasticity mechanisms to epigenetics and the immune system where there is strong evidence to support a functional role in the development of specific depression symptomology. Ultimately we conclude by discussing how novel therapeutic strategies targeting central and peripheral processes might ultimately aid in the development of effective new treatments for MDD and related stress disorders. PMID:26037806

  3. Behavioral effects of developmental methylmercury drinking water exposure in rodents.

    PubMed

    Bisen-Hersh, Emily B; Farina, Marcelo; Barbosa, Fernando; Rocha, Joao B T; Aschner, Michael

    2014-04-01

    Early methylmercury (MeHg) exposure can have long-lasting consequences likely arising from impaired developmental processes, the outcome of which has been exposed in several longitudinal studies of affected populations. Given the large number of newborns at an increased risk of learning disabilities associated with in utero MeHg exposure, it is important to study neurobehavioral alterations using ecologically valid and physiologically relevant models. This review highlights the benefits of using the MeHg drinking water exposure paradigm and outlines behavioral outcomes arising from this procedure in rodents. Combination treatments that exacerbate or ameliorate MeHg-induced effects, and possible molecular mechanisms underlying behavioral impairment are also discussed. PMID:24210169

  4. DEVELOPMENT OF CEREBRAL MICROVASCULAR DYSPLASIA MODEL IN RODENTS

    PubMed Central

    Su, Hua; Hao, Qi; Shen, Fanxia; Zhu, Yiqian; Lee, Chanhung Z.; Young, William L.; Yang, Guo-Yuan

    2008-01-01

    SUMMARY Normal vasculature development of the central nervous system is extremely important because patients with vascular malformations are at life-threatening risk of intracranial hemorrhage or cerebral ischemia. The etiology and pathogenesis of abnormal vasculature development in the central nervous system are unknown, and progress is hampered by the lack of animal models of the human cerebrovascular diseases. Here, we reported our current study on cerebral microvascular dysplasia (CMVD) development. Using vascular endothelial growth factor hyper-stimulation, we demonstrated that aberrant microvessels could be developed in the rodent brain in certain conditions (such as genetic deficient background, local cytokine and chemokine release, or exogenous vessel dilating stimulation) that may speed up focal angiogenesis and lead to cerebral vascular dysplasia. PMID:19066107

  5. Coding odor identity and odor value in awake rodents

    PubMed Central

    Nuez-Parra, Alexia; Li, Anan; Restrepo, Diego

    2014-01-01

    In the last decade, drastic changes in the understanding of the role of the olfactory bulb and piriform cortex in odor detection have taken place through awake behaving recording in rodents. It is clear that odor responses in mitral and granule cells are strikingly different in the olfactory bulb of anesthetized vs. awake animals. In addition, sniff recording has evidenced that mitral cell responses to odors during the sniff can convey information on the odor identity and sniff phase. Moreover, we review studies that show that the mitral cell conveys not only information on odor identity but also on whether the odor is rewarded or not (odor value). Finally, we discuss how the substantial increase in awake behaving recording raises questions for future studies. PMID:24767484

  6. Seroepidemiologic studies of hantavirus infection among wild rodents in California.

    PubMed Central

    Jay, M.; Ascher, M. S.; Chomel, B. B.; Madon, M.; Sesline, D.; Enge, B. A.; Hjelle, B.; Ksiazek, T. G.; Rollin, P. E.; Kass, P. H.; Reilly, K.

    1997-01-01

    A total of 4,626 mammals were serologically tested for antibodies to Sin Nombre virus. All nonrodent species were antibody negative. Among wild rodents, antibody prevalence was 8.5% in murids, 1.4% in heteromyids, and < 0.1% in sciurids. Of 1,921 Peromyscus maniculatus (deer mice), 226 (11.8%) were antibody positive, including one collected in 1975. The highest antibody prevalence (71.4% of 35) was found among P. maniculatus on Santa Cruz Island, off the southern California coast. Prevalence of antibodies among deer mice trapped near sites of human cases (26.8% of 164) was significantly higher than that of mice from other sites (odds ratio = 4.5; 95% confidence interval = 1.7, 11.6). Antibody prevalence increased with rising elevation (> 1,200 meters) and correlated with a spatial cluster of hantavirus pulmonary syndrome cases in the Sierra Nevada. PMID:9204301

  7. [Microbiological diagnosis of emerging arboviral and rodent borne diseases].

    PubMed

    Negredo Antón, Ana Isabel; de Ory Manchón, Fernando; Sánchez-Seco Fariñas, M Paz; Franco Narváez, Leticia; Gegúndez Cámara, M Isabel; Navarro Mari, José M; Tenorio Matanzo, Antonio

    2015-03-01

    Vector borne viruses (VBV) include viruses transmitted by arthropods, rodents and other animals. In Spain the three main autochthonous VBVs causing human diseases are: Toscana, West Nile and Lymphocytic Choriomeningitis viruses. There are also other imported viruses that are potential threats to our public health, due to the presence of competent transmission vectors (dengue and chikungunya viruses in areas infested with Aedes albopictus), or due to the potential person-to-person transmission (Lassa and other viruses causing haemorrhagic fever). The Spanish Society for Infectious Diseases and Clinical Microbiology has responded to the emergence of VBVs by publishing a special issue of Microbiological Proceedings focused on the diagnosis of those emerging vector borne viruses of major concern in our country. PMID:24139129

  8. Amorphous intergranular phases control the properties of rodent tooth enamel

    NASA Astrophysics Data System (ADS)

    Gordon, Lyle M.; Cohen, Michael J.; MacRenaris, Keith W.; Pasteris, Jill D.; Seda, Takele; Joester, Derk

    2015-02-01

    Dental enamel, a hierarchical material composed primarily of hydroxylapatite nanowires, is susceptible to degradation by plaque biofilm-derived acids. The solubility of enamel strongly depends on the presence of Mg2+, F-, and CO32-. However, determining the distribution of these minor ions is challenging. We show—using atom probe tomography, x-ray absorption spectroscopy, and correlative techniques—that in unpigmented rodent enamel, Mg2+ is predominantly present at grain boundaries as an intergranular phase of Mg-substituted amorphous calcium phosphate (Mg-ACP). In the pigmented enamel, a mixture of ferrihydrite and amorphous iron-calcium phosphate replaces the more soluble Mg-ACP, rendering it both harder and more resistant to acid attack. These results demonstrate the presence of enduring amorphous phases with a dramatic influence on the physical and chemical properties of the mature mineralized tissue.

  9. Transmission of Guanarito and Pirital Viruses among Wild Rodents, Venezuela

    PubMed Central

    Milazzo, Mary L.; Cajimat, Maria N.B.; Duno, Gloria; Duno, Freddy; Utrera, Antonio

    2011-01-01

    Samples from rodents captured on a farm in Venezuela in February 1997 were tested for arenavirus, antibody against Guanarito virus (GTOV), and antibody against Pirital virus (PIRV). Thirty-one (48.4%) of 64 short-tailed cane mice (Zygodontomys brevicauda) were infected with GTOV, 1 Alstons cotton rat (Sigmodon alstoni) was infected with GTOV, and 36 (64.3%) of 56 other Alstons cotton rats were infected with PIRV. The results of analyses of field and laboratory data suggested that horizontal transmission is the dominant mode of GTOV transmission in Z. brevicauda mice and that vertical transmission is an important mode of PIRV transmission in S. alstoni rats. The results also suggested that bodily secretions and excretions from most GTOV-infected short-tailed cane mice and most PIRV-infected Alstons cotton rats may transmit the viruses to humans. PMID:22172205

  10. Identification of novel anelloviruses with broad diversity in UK rodents.

    PubMed

    Nishiyama, Shoko; Dutia, Bernadette M; Stewart, James P; Meredith, Anna L; Shaw, Darren J; Simmonds, Peter; Sharp, Colin P

    2014-07-01

    Anelloviruses are a family of small circular ssDNA viruses with a vast genetic diversity. Human infections with the prototype anellovirus, torque teno virus (TTV), are ubiquitous and related viruses have been described in a number of other mammalian hosts. Despite over 15 years of investigation, there is still little known about the pathogenesis and possible disease associations of anellovirus infections, arising in part due to the lack of a robust cell culture system for viral replication or tractable small-animal model. We report the identification of diverse anelloviruses in several species of wild rodents. The viruses are highly prevalent in wood mice (Apodemus sylvaticus) and field voles (Microtus agrestis), detectable at a low frequency in bank voles (Myodes glareolus), but absent from house mice (Mus musculus). The viruses identified have a genomic organization consistent with other anelloviruses, but form two clear phylogenetic groups that are as distinct from each other as from defined genera. PMID:24744300

  11. Identification of novel anelloviruses with broad diversity in UK rodents

    PubMed Central

    Nishiyama, Shoko; Dutia, Bernadette M.; Stewart, James P.; Meredith, Anna L.; Shaw, Darren J.; Simmonds, Peter

    2014-01-01

    Anelloviruses are a family of small circular ssDNA viruses with a vast genetic diversity. Human infections with the prototype anellovirus, torque teno virus (TTV), are ubiquitous and related viruses have been described in a number of other mammalian hosts. Despite over 15 years of investigation, there is still little known about the pathogenesis and possible disease associations of anellovirus infections, arising in part due to the lack of a robust cell culture system for viral replication or tractable small-animal model. We report the identification of diverse anelloviruses in several species of wild rodents. The viruses are highly prevalent in wood mice (Apodemus sylvaticus) and field voles (Microtus agrestis), detectable at a low frequency in bank voles (Myodes glareolus), but absent from house mice (Mus musculus). The viruses identified have a genomic organization consistent with other anelloviruses, but form two clear phylogenetic groups that are as distinct from each other as from defined genera. PMID:24744300

  12. Coding odor identity and odor value in awake rodents.

    PubMed

    Nunez-Parra, Alexia; Li, Anan; Restrepo, Diego

    2014-01-01

    In the last decade, drastic changes in the understanding of the role of the olfactory bulb and piriform cortex in odor detection have taken place through awake behaving recording in rodents. It is clear that odor responses in mitral and granule cells are strikingly different in the olfactory bulb of anesthetized versus awake animals. In addition, sniff recording has evidenced that mitral cell responses to odors during the sniff can convey information on the odor identity and sniff phase. Moreover, we review studies that show that the mitral cell conveys information on not only odor identity but also whether the odor is rewarded or not (odor value). Finally, we discuss how the substantial increase in awake behaving recording raises questions for future studies. PMID:24767484

  13. Deep Brain Stimulation with Simultaneous fMRI in Rodents

    PubMed Central

    Younce, John Robert; Albaugh, Daniel L; Shih, Yen-Yu Ian

    2014-01-01

    In order to visualize the global and downstream neuronal responses to deep brain stimulation (DBS) at various targets, we have developed a protocol for using blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) to image rodents with simultaneous DBS. DBS fMRI presents a number of technical challenges, including accuracy of electrode implantation, MR artifacts created by the electrode, choice of anesthesia and paralytic to minimize any neuronal effects while simultaneously eliminating animal motion, and maintenance of physiological parameters, deviation from which can confound the BOLD signal.Our laboratory has developed a set of procedures that are capable of overcoming most of these possible issues. For electrical stimulation, a homemade tungsten bipolar microelectrode is used, inserted stereotactically at the stimulation site in the anesthetized subject. In preparation for imaging, rodents are fixed on a plastic headpiece and transferred to the magnet bore. For sedation and paralysis during scanning, a cocktail of dexmedetomidine and pancuronium is continuously infused, along with a minimal dose of isoflurane; this preparation minimizes the BOLD ceiling effect of volatile anesthetics. In this example experiment, stimulation of the subthalamic nucleus (STN) produces BOLD responses which are observed primarily in ipsilateral cortical regions, centered in motor cortex. Simultaneous DBS and fMRI allows the unambiguous modulation of neural circuits dependent on stimulation location and stimulation parameters, and permits observation of neuronal modulations free of regional bias. This technique may be used to explore the downstream effects of modulating neural circuitry at nearly any brain region, with implications for both experimental and clinical DBS. PMID:24561922

  14. Central melanopsin projections in the diurnal rodent, Arvicanthis niloticus

    PubMed Central

    Langel, Jennifer L.; Smale, Laura; Esquiva, Gema; Hannibal, Jens

    2015-01-01

    The direct effects of photic stimuli on behavior are very different in diurnal and nocturnal species, as light stimulates an increase in activity in the former and a decrease in the latter. Studies of nocturnal mice have implicated a select population of retinal ganglion cells that are intrinsically photosensitive (ipRGCs) in mediation of these acute responses to light. ipRGCs are photosensitive due to the expression of the photopigment melanopsin; these cells use glutamate and pituitary adenylate cyclase-activating polypeptide (PACAP) as neurotransmitters. PACAP is useful for the study of central ipRGC projections because, in the retina, it is found exclusively within melanopsin cells. Little is known about the central projections of ipRGCs in diurnal species. Here, we first characterized these cells in the retina of the diurnal Nile grass rat using immunohistochemistry (IHC). The same basic subtypes of melanopsin cells that have been described in other mammals were present, but nearly 25% of them were displaced, primarily in its superior region. PACAP was present in 87.7% of all melanopsin cells, while 97.4% of PACAP cells contained melanopsin. We then investigated central projections of ipRGCs by examining the distribution of immunoreactive PACAP fibers in intact and enucleated animals. This revealed evidence that these cells project to the suprachiasmatic nucleus, lateral geniculate nucleus (LGN), pretectum, and superior colliculus. This distribution was confirmed with injections of cholera toxin subunit ? coupled with Alexa Fluor 488 in one eye and Alexa Fluor 594 in the other, combined with IHC staining of PACAP. These studies also revealed that the ventral and dorsal LGN and the caudal olivary pretectal nucleus receive less innervation from ipRGCs than that reported in nocturnal rodents. Overall, these data suggest that although ipRGCs and their projections are very similar in diurnal and nocturnal rodents, they may not be identical. PMID:26236201

  15. DNA Barcoding of Sigmodontine Rodents: Identifying Wildlife Reservoirs of Zoonoses

    PubMed Central

    Müller, Lívia; Gonçalves, Gislene L.; Cordeiro-Estrela, Pedro; Marinho, Jorge R.; Althoff, Sérgio L.; Testoni, André. F.; González, Enrique M.; Freitas, Thales R. O.

    2013-01-01

    Species identification through DNA barcoding is a tool to be added to taxonomic procedures, once it has been validated. Applying barcoding techniques in public health would aid in the identification and correct delimitation of the distribution of rodents from the subfamily Sigmodontinae. These rodents are reservoirs of etiological agents of zoonoses including arenaviruses, hantaviruses, Chagas disease and leishmaniasis. In this study we compared distance-based and probabilistic phylogenetic inference methods to evaluate the performance of cytochrome c oxidase subunit I (COI) in sigmodontine identification. A total of 130 sequences from 21 field-trapped species (13 genera), mainly from southern Brazil, were generated and analyzed, together with 58 GenBank sequences (24 species; 10 genera). Preliminary analysis revealed a 9.5% rate of misidentifications in the field, mainly of juveniles, which were reclassified after examination of external morphological characters and chromosome numbers. Distance and model-based methods of tree reconstruction retrieved similar topologies and monophyly for most species. Kernel density estimation of the distance distribution showed a clear barcoding gap with overlapping of intraspecific and interspecific densities < 1% and 21 species with mean intraspecific distance < 2%. Five species that are reservoirs of hantaviruses could be identified through DNA barcodes. Additionally, we provide information for the description of a putative new species, as well as the first COI sequence of the recently described genus Drymoreomys. The data also indicated an expansion of the distribution of Calomys tener. We emphasize that DNA barcoding should be used in combination with other taxonomic and systematic procedures in an integrative framework and based on properly identified museum collections, to improve identification procedures, especially in epidemiological surveillance and ecological assessments. PMID:24244670

  16. DISTRIBUTION OF OXYTOCIN IN THE BRAIN OF A EUSOCIAL RODENT

    PubMed Central

    Rosen, Greta J.; de Vries, Geert J.; Goldman, Sharry L.; Goldman, Bruce D.; Forger, Nancy G.

    2008-01-01

    Naked mole-rats are highly social rodents that live in large colonies characterized by a rigid social and reproductive hierarchy. Only one female, the queen, breeds. Most colony members are non-reproductive subordinates that work cooperatively to rear the young and maintain an underground burrow system. Little is known about the neurobiological basis of the complex sociality exhibited by this species. The neuropeptide oxytocin (Oxt) modulates social bonding and other social behaviors in many vertebrates. Here we examined the distribution of Oxt immunoreactivity in the brains of male and female naked mole-rats. As in other species, the majority of Oxt-immunoreactive (Oxt-ir) cells were found in the paraventricular and supraoptic nuclei, with additional labeled cells scattered throughout the preoptic and anterior hypothalamic areas. Oxt-ir fibers were found traveling toward and through the median eminence, as well as in the tenia tecta, septum, and nucleus of diagonal band of Broca. A moderate network of fibers covered the bed nucleus of the stria terminalis and preoptic area, and a particularly dense fiber innervation of the nucleus accumbens and substantia innominata was observed. In the brainstem, Oxt-ir fibers were found in the periaqueductal grey, locus coeruleus, parabrachial nucleus, nucleus of the solitary tract, and nuclueus ambiguus. The high levels of Oxt immunoreactivity in the nucleus accumbens and preoptic area are intriguing, given the link in other rodents between Oxt signaling in these regions and maternal behavior. Although only the queen gives birth or nurses pups in a naked mole-rat colony, most individuals actively participate in pup care. PMID:18582538

  17. Pulmonary Toxicity Studies of Lunar Dusts in Rodents

    NASA Technical Reports Server (NTRS)

    Lam, Chiu-wing; James, John T.

    2009-01-01

    NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. Because the toxicity of lunar dust is not known, NASA has tasked its toxicology laboratory to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal/intrapharyngeal instillation. This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies are in progress to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated (ground) lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The results from the instillation studies will be useful for choosing exposure concentrations for the animal inhalation study. The animal inhalation exposure will be conducted with lunar dust simulant prior to the study with the lunar dust. The experiment with the simulate will ensure that the study techniques used with actual lunar dust will be successful. The results of instillation and inhalation studies will reveal the toxicological risk of exposures and are essential for setting exposure limits on lunar dust for astronauts living in the lunar habitat.

  18. Recent Pacific Northwest Laboratory beagle and rodent studies

    SciTech Connect

    Gilbert, E.S.; Park, J.F.; Cross, F.C.; Dagle, G.E.

    1990-07-01

    Analyses based on data from two experimental studies conducted at Pacific Northwest Laboratory will be presented. The first is a lifespan study of beagle dogs exposed to inhaled plutonium. The objectives of this study are, first, to determine the biological effects in dogs of inhaled plutonium at various dose levels, and, second, to obtain dose-effect relationship data that can be used to estimate the risk of these effects in humans. In this study, eighteen-month-old beagle dogs were exposed through inhalation to six different levels and three different types of plutonium. The lowest level corresponds to the maximum permissible level for a plutonium worker, while the highest level is a level at which radiation pneumonitis is likely to cause early death. {sup 239}PuO{sub 2} was chosen because it is the form of plutonium to which people working in nuclear fuel processing and storage industries are likely to be exposed. {sup 238}PuO{sub 2} and {sup 239}Pu(NO{sub 3}){sub 4} were chosen because they result in different spatial and temporal distribution of radiation dose, and thus can provide information on the influence of these factors on risk. The second experiment is a lifespan study of rodents exposed through inhalation to radon and radon progeny. For the rodent experiments to be considered in this presentation, exposures were initiated at about 90 days of age at rates of 5, 50, and 500 WLM per week. Cumulative exposure levels were 320, 640, 1280, 2560, and 5120 WLM for animals exposed at 50 and 500 WLM per week, and 320 WLM for animals exposed at 5 WLM per week. 7 refs.

  19. Deep brain stimulation with simultaneous FMRI in rodents.

    PubMed

    Younce, John Robert; Albaugh, Daniel L; Shih, Yen-Yu Ian

    2014-01-01

    In order to visualize the global and downstream neuronal responses to deep brain stimulation (DBS) at various targets, we have developed a protocol for using blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) to image rodents with simultaneous DBS. DBS fMRI presents a number of technical challenges, including accuracy of electrode implantation, MR artifacts created by the electrode, choice of anesthesia and paralytic to minimize any neuronal effects while simultaneously eliminating animal motion, and maintenance of physiological parameters, deviation from which can confound the BOLD signal. Our laboratory has developed a set of procedures that are capable of overcoming most of these possible issues. For electrical stimulation, a homemade tungsten bipolar microelectrode is used, inserted stereotactically at the stimulation site in the anesthetized subject. In preparation for imaging, rodents are fixed on a plastic headpiece and transferred to the magnet bore. For sedation and paralysis during scanning, a cocktail of dexmedetomidine and pancuronium is continuously infused, along with a minimal dose of isoflurane; this preparation minimizes the BOLD ceiling effect of volatile anesthetics. In this example experiment, stimulation of the subthalamic nucleus (STN) produces BOLD responses which are observed primarily in ipsilateral cortical regions, centered in motor cortex. Simultaneous DBS and fMRI allows the unambiguous modulation of neural circuits dependent on stimulation location and stimulation parameters, and permits observation of neuronal modulations free of regional bias. This technique may be used to explore the downstream effects of modulating neural circuitry at nearly any brain region, with implications for both experimental and clinical DBS. PMID:24561922

  20. Sero-Prevalence of Rodent Pathogens in India

    PubMed Central

    Manjunath, Shrruthi; Kulkarni, Prachet G.; Nagavelu, Krishnaveni; Samuel, Rosa J.; Srinivasan, Sandhya; Ramasamy, Nandhini; Hegde, Nagendra R.; Gudde, Ramachandra S.

    2015-01-01

    Health monitoring is an integral part of laboratory animal quality standards. However, current or past prevalence data as well as regulatory requirements dictate the frequency, type and the expanse of health monitoring. In an effort to understand the prevalence of rodent pathogens in India, a preliminary study was carried out by sero-epidemiology. Sera samples obtained from 26 public and private animal facilities were analyzed for the presence of antibodies against minute virus of mice (MVM), ectromelia virus (ECTV), lymphocytic choriomeningitis virus (LCMV), mouse hepatitis virus (MHV), Sendai virus (SeV), and Mycoplasma pulmonis in mice, and SeV, rat parvo virus (RPV), Kilhams rat virus (KRV) and sialodacryoadenitis virus (SDAV) in rats, by sandwich ELISA. It was observed that MHV was the most prevalent agent followed by Mycoplasma pulmonis and MVM in mice, and SDAV followed by RPV were prevalent in rats. On the other hand, none of the samples were positive for ECTV in mice, or SeV or KRV in rats. Multiple infections were common in both mice and rats. The incidence of MHV and Mycoplasma pulmonis was higher in facilities maintained by public organizations than in vivaria of private organizations, although the difference was not statistically different. On the other hand the prevalence of rodent pathogens was significantly higher in the northern part of India than in the South. These studies form the groundwork for detailed sero-prevalence studies which should further lay the foundations for country-specific guidelines for health monitoring of laboratory animals. PMID:26158453

  1. Sero-Prevalence of Rodent Pathogens in India.

    PubMed

    Manjunath, Shrruthi; Kulkarni, Prachet G; Nagavelu, Krishnaveni; Samuel, Rosa J; Srinivasan, Sandhya; Ramasamy, Nandhini; Hegde, Nagendra R; Gudde, Ramachandra S

    2015-01-01

    Health monitoring is an integral part of laboratory animal quality standards. However, current or past prevalence data as well as regulatory requirements dictate the frequency, type and the expanse of health monitoring. In an effort to understand the prevalence of rodent pathogens in India, a preliminary study was carried out by sero-epidemiology. Sera samples obtained from 26 public and private animal facilities were analyzed for the presence of antibodies against minute virus of mice (MVM), ectromelia virus (ECTV), lymphocytic choriomeningitis virus (LCMV), mouse hepatitis virus (MHV), Sendai virus (SeV), and Mycoplasma pulmonis in mice, and SeV, rat parvo virus (RPV), Kilham's rat virus (KRV) and sialodacryoadenitis virus (SDAV) in rats, by sandwich ELISA. It was observed that MHV was the most prevalent agent followed by Mycoplasma pulmonis and MVM in mice, and SDAV followed by RPV were prevalent in rats. On the other hand, none of the samples were positive for ECTV in mice, or SeV or KRV in rats. Multiple infections were common in both mice and rats. The incidence of MHV and Mycoplasma pulmonis was higher in facilities maintained by public organizations than in vivaria of private organizations, although the difference was not statistically different. On the other hand the prevalence of rodent pathogens was significantly higher in the northern part of India than in the South. These studies form the groundwork for detailed sero-prevalence studies which should further lay the foundations for country-specific guidelines for health monitoring of laboratory animals. PMID:26158453

  2. Arctic Small Rodents Have Diverse Diets and Flexible Food Selection

    PubMed Central

    Soininen, Eeva M.; Ravolainen, Virve T.; Brthen, Kari Anne; Yoccoz, Nigel G.; Gielly, Ludovic; Ims, Rolf A.

    2013-01-01

    The ecology of small rodent food selection is poorly understood, as mammalian herbivore food selection theory has mainly been developed by studying ungulates. Especially, the effect of food availability on food selection in natural habitats where a range of food items are available is unknown. We studied diets and selectivity of grey-sided voles (Myodes rufocanus) and tundra voles (Microtus oeconomus), key herbivores in European tundra ecosystems, using DNA metabarcoding, a novel method enabling taxonomically detailed diet studies. In order to cover the range of food availabilities present in the wild, we employed a large-scale study design for sampling data on food availability and vole diets. Both vole species had ingested a range of plant species and selected particularly forbs and grasses. Grey-sided voles also selected ericoid shrubs and tundra voles willows. Availability of a food item rarely affected its utilization directly, although seasonal changes of diets and selection suggest that these are positively correlated with availability. Moreover, diets and selectivity were affected by availability of alternative food items. These results show that the focal sub-arctic voles have diverse diets and flexible food preferences and rarely compensate low availability of a food item with increased searching effort. Diet diversity itself is likely to be an important trait and has previously been underrated owing to methodological constraints. We suggest that the roles of alternative food item availability and search time limitations for small rodent feeding ecology should be investigated. Nomenclature Annotated Checklist of the Panarctic Flora (PAF), Vascular plants. Available at: http://nhm2.uio.no/paf/, accessed 15.6.2012. PMID:23826371

  3. Modelling cognitive affective biases in major depressive disorder using rodents

    PubMed Central

    Hales, Claire A; Stuart, Sarah A; Anderson, Michael H; Robinson, Emma S J

    2014-01-01

    Major depressive disorder (MDD) affects more than 10% of the population, although our understanding of the underlying aetiology of the disease and how antidepressant drugs act to remediate symptoms is limited. Major obstacles include the lack of availability of good animal models that replicate aspects of the phenotype and tests to assay depression-like behaviour in non-human species. To date, research in rodents has been dominated by two types of assays designed to test for depression-like behaviour: behavioural despair tests, such as the forced swim test, and measures of anhedonia, such as the sucrose preference test. These tests have shown relatively good predictive validity in terms of antidepressant efficacy, but have limited translational validity. Recent developments in clinical research have revealed that cognitive affective biases (CABs) are a key feature of MDD. Through the development of neuropsychological tests to provide objective measures of CAB in humans, we have the opportunity to use ‘reverse translation’ to develop and evaluate whether similar methods are suitable for research into MDD using animals. The first example of this approach was reported in 2004 where rodents in a putative negative affective state were shown to exhibit pessimistic choices in a judgement bias task. Subsequent work in both judgement bias tests and a novel affective bias task suggest that these types of assay may provide translational methods for studying MDD using animals. This review considers recent work in this area and the pharmacological and translational validity of these new animal models of CABs. Linked Articles This article is part of a themed section on Animal Models in Psychiatry Research. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-20 PMID:24467454

  4. Nutritional disorders in tropical neurology.

    PubMed

    Romn, Gustavo C

    2013-01-01

    About three-fourths of the total world population live in the tropics but consume only 6% of worldwide food production and contribute 15% of the world's net revenue explaining the short life expectancy, high infantile mortality, and poor daily caloric intake; moreover, lack of clean drinking water and deficient sanitation promote water-borne infections, diarrhea, and risk of malabsorption that contribute to the prevalence of malnutrition in the tropics. One-third of the world's population consumes insufficient iodine increasing the risk for mental retardation and deafness due to maternal hypothyroidism. The main nutritional syndromes comprise protein-energy malnutrition (marasmus and kwashiorkor); nutritional neuropathies, myelopathies and neuromyelopathies, as well as specific deficiencies of vitamins and micronutrients including iodine, iron, zinc, and selenium. PMID:23829926

  5. Fluid Mechanics of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Lighthill, James, Sir

    Typhoons in the northwest Pacific and hurricanes in the northeast Atlantic are particular instances of a global phenomenon with frequently disastrous consequences known as the Tropical Cyclone (TC). This is an intense cyclone, generated over a tropical ocean with kinetic energy 1018 J or more, which extends over several hundred kilometres and yet is above all characterized by its calm central region: ``the eye of the storm''. In a TC (not, of course, to be confused with such completely different phenomena as tornadoes) both the energy input and its dissipation mainly occur within that boundary layer between air and ocean which, at high TC wind speeds of 50-60 m/s, comprises essentially ``a third fluid'': ocean spray. Afterwards, as a TC reaches land, disastrous effects of several different kinds may occur, and this paper outlines how fluid mechanics contributes towards worldwide struggles to reduce the human impact of TC disasters.

  6. Health crusades and tropical diseases.

    PubMed

    Weller, T H

    1980-03-01

    Worldwide attempts to eradicate yaws, malaria, and smallpox have all been effective to varying extents, and all have taught some valuable lessons that should be taken into account as a new global crusade is mounted against tropical diseases. But it should not be forgotten that infectious disease remains a major public health problem in the U.S., and new diseases are arising to replace those already vanquished. PMID:7399467

  7. String networks as tropical curves

    NASA Astrophysics Data System (ADS)

    Ray, Koushik

    2008-09-01

    A prescription for obtaining supergravity solutions for planar (p,q)-string networks is presented, based on earlier results. It shows that networks may be looked upon as tropical curves emerging as the spine of the amoeba of a holomorphic curve in M-theory. The Khler potential of supergravity is identified with the corresponding Ronkin function. Implications of this identification in counting dyons is discussed.

  8. Simulation of Tropical Biomass Burning

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Guo, Zitian

    1996-01-01

    The research objectives that were achieved during the course of our studies include the following: (1) Over the last few years, a model has been developed in the Atmospheric Chemistry and Dynamics Branch at Ames Research Center in collaboration with the Physics Department at San Jose State University. It is referred to as the Global/Regional Atmospheric Chemistry Event Simulator (GRACES). Currently, the GRACES model system combines an atmospheric chemistry and transport model, and a regional mesoscale meteorological model. Therefore this system is suitable for simulating the conditions observed by the tropical observation missions, such as the Pacific Exploratory Mission in the 'Tropics (PEM-Tropics), Study of Ozone and Nitrogen oxides Experiment (SONEX), and other periods. Specifically, the research carried out included the evaluation of the behavior of several components of the MM5 (I.e., Meteorological Model 5, version 2) and the GRACES combined modeling system. We initiated research on (a) the ability of the MM5 model to assimilate downward vertical velocities at least as high as the analyses, (b) the ability of the Graces model to incorporate the vertical velocities from MM5, and (c) other factors related to transport patterns required to transport CO in the observed manner. We carried out improved calculations of the transport of tracers for both NASA airborne missions, SONEX and PEM-Tropics. We also made improved source strength estimates fopr isoprene dust, and similar emissions from the Earths surface. This required the use of newly available databases on the Earth's surface and vegetation. We completed atmospheric chemistry simulations of radicals and nitrogen oxide species. We have greatly improved the handling of cumulonimnbus convection by modifing an existing scheme.

  9. Medical geochemistry of tropical environments

    NASA Astrophysics Data System (ADS)

    Dissanayake, C. B.; Chandrajith, Rohana

    1999-10-01

    Geochemically, tropical environments are unique. This uniqueness stems from the fact that these terrains are continuously subjected to extreme rainfall and drought with resulting strong geochemical fractionation of elements. This characteristic geochemical partitioning results in either severe depletion of elements or accumulation to toxic levels. In both these situations, the effect on plant, animal and human health is marked. Medical geochemistry involves the study of the relationships between the geochemistry of the environment in which we live and the health of the population living in this particular domain. Interestingly, the relationships between geochemistry and health are most marked in the tropical countries, which coincidentally are among the poorest in the world. The very heavy dependence on the immediate environment for sustainable living in these lands enables the medical geochemist to observe correlations between particular geochemical provinces and the incidence of certain diseases unique to these terrains. The aetiology of diseases such as dental and skeletal fluorosis, iodine deficiency disorders, diseases of humans and animals caused by mineral imbalances among others, lie clearly in the geochemical environment. The study of the chemistry of the soils, water and stream sediments in relation to the incidence of geographically distributed diseases in the tropics has not only opened up new frontiers in multidisciplinary research, but has offered new challenges to the medical profession to seriously focus attention on the emerging field of medical geochemistry with the collaboration of geochemists and epidemiologists.

  10. Rain from Tropical Storm Noel

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Though not the most powerful storm of the 2007 Atlantic Hurricane season, Tropical Storm Noel was among the most deadly. Only Category 5 Hurricane Felix and its associated flooding had a higher toll. The slow-moving Tropical Storm Noel inundated the Dominican Republic, Haiti, Jamaica, Cuba, and the Bahamas with heavy rain between October 28 and November 1, 2007. The resulting floods and mudslides left at least 115 dead and thousands homeless throughout the Caribbean, reported the Associated Press on November 2, 2007. This image shows the distribution of the rainfall that made Noel a deadly storm. The image shows rainfall totals as measured by the Multi-satellite Precipitation Analysis (MPA) at NASA Goddard Space Flight Center from October 26 through November 1, 2007. The analysis is based on measurements taken by the Tropical Rainfall Measuring Mission (TRMM) satellite. The heaviest rainfall fell in the Dominican Republic and the Bahamas, northeast of Noel's center. Areas of dark red show that rainfall totals over the south-central Dominican Republic and parts of the Bahamas were over 551 millimeters (21 inches). Much of eastern Hispaniola, including both the Dominican Republic and Haiti received at least 200 mm (about 8 inches) of rain, shown in yellow. Rainfall totals over Haiti and Cuba were less, with a range of at least 50 mm (2 inches) to over 200 mm (8 inches).

  11. Ecotoxicology of tropical marine ecosystems

    SciTech Connect

    Peters, E.C.; Gassman, N.J.; Firman, J.C.; Richmond, R.H.; Power, E.A.

    1997-01-01

    The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available on impacts of chemical stressors on mangrove forests, seagrass meadows, and coral reefs are discussed in the context of ecosystem management and ecological risk assessment. Three classes of pollutants have received attention: heavy metals, petroleum, and synthetic organics. Heavy metals have been detected in all three ecosystems, causing physiological stress, reduced reproductive success, and outright mortality in associated invertebrates and fishes. Oil spills have been responsible for the destruction of entire coastal shallow-water communities, with recovery requiring years. Herbicides are particularly detrimental to mangroves and seagrasses and adversely affect the animal-algal symbioses in corals. Pesticides interfere with chemical cues responsible for key biological processes, including reproduction and recruitment of a variety of organisms. Information is lacking with regard to long-term recovery, indicator species, and biomarkers for tropical communities. Critical areas that are beginning to be addressed include the development of appropriate benchmarks for risk assessment, baseline monitoring criteria, and effective management strategies to protect tropical marine ecosystems in the face of mounting anthropogenic disturbance.

  12. Neglected tropical diseases in Central America and Panama: review of their prevalence, populations at risk and impact on regional development.

    PubMed

    Hotez, Peter J; Woc-Colburn, Laila; Bottazzi, Maria Elena

    2014-08-01

    A review of the literature since 2009 reveals a staggering health and economic burden resulting from neglected tropical diseases in Panama and the six countries of Central America (referred to collectively here as 'Central America'). Particularly at risk are the 10.2million people in the region who live on less than $2 per day, mostly in Guatemala, Honduras, Nicaragua and El Salvador. Indigenous populations are especially vulnerable to neglected tropical diseases. Currently, more than 8million Central American children require mass drug treatments annually (or more frequently) for their intestinal helminth infections, while vector-borne diseases are widespread. Among the vector-borne parasitic infections, almost 40% of the population is at risk for malaria (mostly Plasmodium vivax infection), more than 800,000 people live with Chagas disease, and up to 39,000 people have cutaneous leishmaniasis. In contrast, an important recent success story is the elimination of onchocerciasis from Central America. Dengue is the leading arbovirus infection with 4-5million people affected annually and hantavirus is an important rodent-borne viral neglected tropical disease. The leading bacterial neglected tropical diseases include leptospirosis and trachoma, for which there are no disease burden estimates. Overall there is an extreme dearth of epidemiological data on neglected tropical diseases based on active surveillance as well as estimates of their economic impact. Limited information to date, however, suggests that neglected tropical diseases are a major hindrance to the region's economic development, in both the most impoverished Central American countries listed above, as well as for Panama and Costa Rica where a substantial (but largely hidden) minority of people live in extreme poverty. PMID:24846528

  13. Oncogene activation in spontaneous and chemically induced rodent tumors: implications for risk analysis

    SciTech Connect

    Reynolds, S.H.; Stowers, S.J.; Patterson, R.M.; Maronpot, R.R.; Anderson, M.W.

    1988-06-01

    The validity of rodent tumor end points in assessing the potential hazards of chemical exposure to humans is a somewhat controversial but very important issue since most chemicals are classified as potentially hazardous to humans on the basis of long-term carcinogenesis studies in rodents. The ability to distinguish between genotoxic, cytotoxic, or receptor-mediated promotion effects of chemical treatment would aid in the interpretation of rodent carcinogenesis data. Activated oncogenes in spontaneously occurring and chemically induced rodent tumors were examined and compared as one approach to determine the mechanism by which chemical treatment caused an increased incidence of rodent tumors. Different patterns of activated oncogenes were found not only in spontaneous versus chemically induced mouse liver tumors but also in a variety of spontaneous rat tumors versus chemically induced rat lung tumors. In the absence of cytotoxic effects, it could be argued that the chemicals in question activated protooncogenes by a direct genotoxic mechanism. These results provided a basis for the analysis of activated oncogenes in spontaneous and chemically induced rodent tumors to provide information at a molecular level to aid in the extrapolation of rodent carcinogenesis data to human risk assessment.

  14. Tropical forest preservation using economic incentives

    SciTech Connect

    Katzman, M.T. ); Cale, W.G. Jr. )

    1990-12-01

    The authors address the problem of deforestation of the tropical forests in terms of economic factors. They outline the global effects, such as hydrological and climatological changes, that apparently small scale deforestation has, when the forest is destroyed in many different places. The authors suggest that industrialized nations should offer economic incentives for tropical nations to save their forests, since all the world will suffer the effects of tropical deforestation.

  15. Landform and surface attributes for prediction of rodent burrows in the Western Usambara Mountains, Tanzania.

    PubMed

    Meliyo, Joel L; Massawe, Boniface H J; Msanya, Balthazar M; Kimaro, Didas N; Hieronimo, Proches; Mulungu, Loth S; Kihupi, Nganga I; Deckers, Jozef A; Gulinck, Hubert; Leirs, Herwig

    2014-07-01

    Previous studies suggest that rodent burrows, a proxy for rodent population are important for predicting plague risk areas. However, studies that link landform, surface attributes and rodent burrows in the Western Usambara Mountains in Tanzania are scanty. Therefore, this study was conducted in plague endemic area of the Western Usambara Mountains in northern, Tanzania, to explore the relationship between rodent burrows, and landform and surface attributes. The study was carried out in three areas corresponding to high (Lokome), medium (Lukozi) and low.(Mwangoi) frequency of reported plague cases. Data were collected from 117, 200 and 170 observation sites for Lokome, Lukozi and Mwangoi, respectively using 100 m x 200 m quadrats. Remote sensing and field surveys were used to collect data on landform and surface attributes. Rodent burrows were surveyed and quantified by counting the number of burrows in 20m x 20m grids demarcated on the main 100m x 200m quadrats. The collected data were analysed in R software using boosted regression trees (BRT) technique. Rodent burrows were found at an elevation of above 1600m in the high and medium plague frequency landscapes. No burrows were found in the low plague frequency landscape situated below 1500m. BRT analysis shows a significant relationship between landform characteristics and rodent burrows in both high and medium plague frequency landscapes. Overall, elevation and hillshade are the most important determinants of rodent burrow distribution in the studied landscapes. It is concluded that in high altitudes, specific landform attributes (hill-shade, slope, elevation) and vegetation cover- favour rodent burrowing. PMID:26867278

  16. Camera Trapping: A Contemporary Approach to Monitoring Invasive Rodents in High Conservation Priority Ecosystems

    PubMed Central

    Rendall, Anthony R.; Sutherland, Duncan R.; Cooke, Raylene; White, John

    2014-01-01

    Invasive rodent species have established on 80% of the world's islands causing significant damage to island environments. Insular ecosystems support proportionally more biodiversity than comparative mainland areas, highlighting them as critical for global biodiversity conservation. Few techniques currently exist to adequately detect, with high confidence, species that are trap-adverse such as the black rat, Rattus rattus, in high conservation priority areas where multiple non-target species persist. This study investigates the effectiveness of camera trapping for monitoring invasive rodents in high conservation areas, and the influence of habitat features and density of colonial-nesting seabirds on rodent relative activity levels to provide insights into their potential impacts. A total of 276 camera sites were established and left in situ for 8 days. Identified species were recorded in discrete 15 min intervals, referred to as events. In total, 19 804 events were recorded. From these, 31 species were identified comprising 25 native species and six introduced. Two introduced rodent species were detected: the black rat (90% of sites), and house mouse Mus musculus (56% of sites). Rodent activity of both black rats and house mice were positively associated with the structural density of habitats. Density of seabird burrows was not strongly associated with relative activity levels of rodents, yet rodents were still present in these areas. Camera trapping enabled a large number of rodents to be detected with confidence in site-specific absences and high resolution to quantify relative activity levels. This method enables detection of multiple species simultaneously with low impact (for both target and non-target individuals); an ideal strategy for monitoring trap-adverse invasive rodents in high conservation areas. PMID:24599307

  17. Seed removal by scatter-hoarding rodents: the effects of tannin and nutrient concentration.

    PubMed

    Wang, Bo; Yang, Xiaolan

    2015-04-01

    The mutualistic interaction between scatter-hoarding rodents and seed plants have a long co-evolutionary history. Plants are believed to have evolved traits that influence the foraging behavior of rodents, thus increasing the probability of seed removal and caching, which benefits the establishment of seedlings. Tannin and nutrient content in seeds are considered among the most essential factors in this plant-animal interaction. However, most previous studies used different species of plant seeds, rendering it difficult to tease apart the relative effect of each single nutrient on rodent foraging behavior due to confounding combinations of nutrient contents across seed species. Hence, to further explore how tannin and different nutritional traits of seed affect scatter-hoarding rodent foraging preferences, we manipulated tannin, fat, protein and starch content levels, and also seed size levels by using an artificial seed system. Our results showed that both tannin and various nutrients significantly affected rodent foraging preferences, but were also strongly affected by seed size. In general, rodents preferred to remove seeds with less tannin. Fat addition could counteract the negative effect of tannin on seed removal by rodents, while the effect of protein addition was weaker. Starch by itself had no effect, but it interacted with tannin in a complex way. Our findings shed light on the effects of tannin and nutrient content on seed removal by scatter-hoarding rodents. We therefore, believe that these and perhaps other seed traits should interactively influence this important plant-rodent interaction. However, how selection operates on seed traits to counterbalance these competing interests/factors merits further study. PMID:25625425

  18. Detection of Leishmania donovani and L. tropica in Ethiopian wild rodents.

    PubMed

    Kassahun, Aysheshm; Sadlova, Jovana; Dvorak, Vit; Kostalova, Tatiana; Rohousova, Iva; Frynta, Daniel; Aghova, Tatiana; Yasur-Landau, Daniel; Lemma, Wessenseged; Hailu, Asrat; Baneth, Gad; Warburg, Alon; Volf, Petr; Votypka, Jan

    2015-05-01

    Human visceral (VL, also known as Kala-azar) and cutaneous (CL) leishmaniasis are important infectious diseases affecting countries in East Africa that remain endemic in several regions of Ethiopia. The transmission and epidemiology of the disease is complicated due to the complex life cycle of the parasites and the involvement of various Leishmania spp., sand fly vectors, and reservoir animals besides human hosts. Particularly in East Africa, the role of animals as reservoirs for human VL remains unclear. Isolation of Leishmania donovani parasites from naturally infected rodents has been reported in several endemic countries; however, the status of rodents as reservoirs in Ethiopia remains unclear. Here, we demonstrated natural Leishmania infections in rodents. Animals were trapped in 41 localities of endemic and non-endemic areas in eight geographical regions of Ethiopia and DNA was isolated from spleens of 586 rodents belonging to 21 genera and 38 species. Leishmania infection was evaluated by real-time PCR of kinetoplast (k)DNA and confirmed by sequencing of the PCR products. Subsequently, parasite species identification was confirmed by PCR and DNA sequencing of the 18S ribosomal RNA internal transcribed spacer one (ITS1) gene. Out of fifty (8.2%) rodent specimens positive for Leishmania kDNA-PCR and sequencing, 10 were subsequently identified by sequencing of the ITS1 showing that five belonged to the L. donovani complex and five to L. tropica. Forty nine kDNA-positive rodents were found in the endemic localities of southern and eastern Ethiopia while only one was identified from northwestern Ethiopia. Moreover, all the ten ITS1-positive rodents were captured in areas where human leishmaniasis cases have been reported and potential sand fly vectors occur. Our findings suggest the eco-epidemiological importance of rodents in these foci of leishmaniasis and indicate that rodents are likely to play a role in the transmission of leishmaniasis in Ethiopia, possibly as reservoir hosts. PMID:25700710

  19. Microbial safety of tropical and sub-tropical fruit. in Volume 1 – General Physiology, Quality and Handling of Tropical and Sub-tropical Fruits, Postharvest Biology & Technology of Tropical and Sub-tropical Fruits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter describes past outbreaks, potential routes of contamination for specific, potential interventions, and operational procedures associated with tropical and sub-tropical fruits. Various pre-harvest sources can result in contamination of fruits; and survival and growth of pathogens on who...

  20. Ancient tropical climates warm San Francisco gathering

    SciTech Connect

    Kerr, R.A.

    1994-01-14

    Climate records preserved in the Greenland ice sheet got a lot of the attention at the fall meeting of the American Geophysical Union (AGU) in San Francisco last month, but ancient tropical records were a rival attraction. In talks scattered in unrelated sessions, researchers reported a possible role for the tropics in driving the last ice age, a link between high latitudes and the tropics that may have redirected human evolution, and a tropical climate periodicity that may fill a gap in the understanding of climate variability.

  1. The ecology of tropical lakes and rivers

    SciTech Connect

    Payne, A.I.

    1986-01-01

    This is self-contained text reviewing tropical limnology. It discusses a number of communities in detail, including plankton, benthic regions, and the water margins. It introduces the characteristic types and assemblies of animals and plants from tropical communities. The measurement and relative magnitude of such quantifiable aspects as abundance, biomass, primary production, secondary production, and decomposition are all outlined, drawing together the diverse threads of freshwater ecology over one of the earth's climatic belts. Deals with use and abuse of water in the tropics and looks at problems of diversity and diversification in tropical waters.

  2. Nitrous oxide flux following tropical land clearing

    NASA Technical Reports Server (NTRS)

    Luizao, Flavio; Luizao, Regina; Matson, Pamela; Livingston, Gerald; Vitousek, Peter

    1989-01-01

    The importance of seasonal cycles of N2O flux from tropical ecosystems and the possibility that tropical deforestation could contribute to the ongoing global increase in N2O concentrations were assessed by measuring N2O flux from forest, cleared land, and pasture over an annual cycle in the central Amazon. A pasture that had been converted from tropical forest had threefold greater annual N2O flux than a paired forest site; similar results were obtained in spot measurements in other pastures. If these results are general, such tropical pastures represent a globally significant source of increased N2O.

  3. New host, geographic records, and histopathologic studies of Angiostrongylus spp (Nematoda: Angiostrongylidae) in rodents from Argentina with updated summary of records from rodent hosts and host specificity assessment

    PubMed Central

    Robles, María del Rosario; Kinsella, John M; Galliari, Carlos; Navone, Graciela T

    2016-01-01

    To date, 21 species of the genus Angiostrongylus (Nematoda: Angiostrongylidae) have been reported around the world, 15 of which are parasites of rodents. In this study, new host, geographic records, and histopathologic studies of Angiostrongylus spp in sigmodontine rodents from Argentina, with an updated summary of records from rodent hosts and host specificity assessment, are provided. Records of Angiostrongylus costaricensis from Akodon montensis andAngiostrongylus morerai from six new hosts and geographical localities in Argentina are reported. The gross and histopathologic changes in the lungs of the host species due to angiostrongylosis are described. Published records of the genus Angiostrongylus from rodents and patterns of host specificity are presented. Individual Angiostrongylusspecies parasitise between one-19 different host species. The most frequent values of the specificity index (STD) were between 1-5.97. The elevated number of host species (n = 7) of A. morerai with a STD = 1.86 is a reflection of multiple systematic studies of parasites from sigmodontine rodents in the area of Cuenca del Plata, Argentina, showing that an increase in sampling effort can result in new findings. The combination of low host specificity and a wide geographic distribution of Angiostrongylus spp indicates a troubling epidemiological scenario although, as yet, no human cases have been reported. PMID:26982178

  4. Taphonomic alterations by the rodent species woodland vole (Microtus pinetorum) upon human skeletal remains.

    PubMed

    Pokines, James T

    2015-12-01

    This forensic case report describes the taphonomic effects of woodland vole (Microtus pinetorum) upon a set of skeletonized human remains recovered in Massachusetts, USA. Remains of an individual of this rodent species were discovered where it had been nesting inside the human cranium. Fine, parallel grooves indicative of small rodent gnawing were noted on multiple postcranial elements, and all isolated grooves were consistent in size with the incisors of this species. Other taphonomic alterations to these remains include some gnawing damage and dispersal by large carnivores. This case represents the first report of this rodent species affecting human remains. PMID:26358959

  5. A TROPICAL GARDEN FLORA, PLANTS CULTIVATED IN THE HAWAIIAN ISLANDS AND OTHER TROPICAL AREAS.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pemberton, R.W. A Tropical Garden Flora, Plants Cultivated in the Hawaiian Islands and Other Tropical Areas. Economic Botany This is an invited book review of an important new reference book on plants cultivated in the tropical and subtropical areas of the world. This is the long awaited update of ...

  6. The Role of the Tropics in Abrupt Climate Changes

    SciTech Connect

    Fedorov, Alexey

    2013-12-07

    Topics addressed include: abrupt climate changes and ocean circulation in the tropics; what controls the ocean thermal structure in the tropics; a permanent El Niño in paleoclimates; the energetics of the tropical ocean.

  7. Methane Emission from Tropical Rivers

    NASA Astrophysics Data System (ADS)

    Sawakuchi, H. O.; Rasera, M. F. F. L.; Krusche, A. V.; Ballester, M. V. R.

    2012-04-01

    Inland water is already known as an important source of methane to atmosphere. Methane is produced in anaerobic environments usually find in lakes and floodplain bottom sediment. It is the main reason that almost all information regarding methane flux come from this environments. However, while floodplain dries during low water season reducing methanogenesis, rivers keep the capacity to emit methane throughout the year. Here we present preliminary results of CH4 flux measurements done in 6 large tropical rivers within the Amazon basin. We measured 17 areas using floating chamber during dry (low water) season, between September and November of 2011, in Amazon river mainstem, Araguaia, Xingu, Tapajós, Madeira, and Negro Rivers. Measured fluxes of all rivers ranged from 59.3 to 2974.4 mmol m-2 yr-1. Geomorphologic structure of channels is one important factor that contributes to this high heterogeneity due to development of low flow velocity depositional settings allowing formation of anoxic zones in rivers. Hydraulic and sediment barriers in the confluence of river channels promote the generation of natural dams which function as a trap for the suspension load favoring the deposition of organic rich muds. This kind of environment is very different from common river channels and has a stronger potential of methane emission. Average values of our flux measurements for this two river environments show that depositional areas can have much higher fluxes than the main channel, 1089.6 and 163.1 mmol m-2 yr-1, respectively. Hence, CH4 flux from these depositional zones is similar to some tropical floodplain lakes and reservoirs. Although the low flux from channel, the area covered by water is very large resulting in a significant contribution to the regional methane emission to the atmosphere. Moreover, mapping the area of these depositional river zones will give us a better idea of the magnitude of methane flux from tropical rivers.

  8. Evidence for rodent-common and species-typical limb and digit use in eating, derived from a comparative analysis of ten rodent species.

    PubMed

    Whishaw, I Q; Sarna, J R; Pellis, S M

    1998-11-01

    Order Rodentia comprises a vast portion of mammalian species (1814 species), which occupy extremely diverse habitats requiring very distinct motor specializations (e.g. burrowing, hopping, climbing, flying and swimming). Although early classification of paw use ability suggests rodents are impoverished relative to primates and make little use of their paws, there have been no systematic investigations of paw use in rodents. The present study was undertaken to describe limb/paw movements in a variety of common rodents. The movements used for handling sunflower seeds and other foods were videorecorded and analyzed in the guinea pig (Cavia porcellus), Mongolian gerbil (Meriones unguiculatus), Syrian hamster (Mesocricetus auratus), laboratory mouse (Mus musculus), laboratory rat (Rattus norvegicus), gray squirrel (Sciurus carolinensis), red squirrel (Tamiasciurus hudsonicus), Richardson's ground squirrel (Spermophilus richardsonni), prairie dog (Cynomus parvidens), and Canadian beaver (Castor americanus). The results suggested five order-common movements of food handling: (1) locating food by sniffing, (2) grasping food by mouth, (3) sitting back on the haunches to eat, (4) grasping the food using an elbow-in movement, and (5) manipulate the food with the digits. Different species displayed species-typical specializations including (1) bilateral grasping with the paws (gerbil), (2) unilateral grasping with a paw (beaver), (3) unilateral holding (ground squirrels), (4) various grip and digit postures (all species), (5) unilateral object removal from the mouth (gerbil), (6) bilateral thumb holding (squirrels), and (7) simultaneous holding/manipulation of two objects (squirrels). Only the guinea pig did not handle food with its paws, suggesting its behavior is regressive. The existence of a core pattern of paw and digit use in rodents suggests that skilled limb and paw movements originate at least with the common ancestors of the rodent, and likely the common ancestor to rodent and primate lineages, while species-typical movements suggest specialization/regression of limb use has occurred in a number of mammalian orders. PMID:9821545

  9. A new gustometer for taste testing in rodents.

    PubMed

    Spector, Alan C; Blonde, Ginger D; Henderson, Ross P; Treesukosol, Yada; Hendrick, Paul; Newsome, Ryan; Fletcher, Fred H; Tang, Te; Donaldson, James A

    2015-03-01

    In recent years, to circumvent the interpretive limitations associated with intake tests commonly used to assess taste function in rodents, investigators have developed devices called gustometers to deliver small volumes of taste samples and measure immediate responses, thereby increasing confidence that the behavior of the animal is under orosensory control. Most of these gustometers can be used to measure unconditioned licking behavior to stimuli presented for short durations and/or can be used to train the animal to respond to various fluid stimuli differentially so as to obtain a reward and/or avoid punishment. Psychometric sensitivity and discrimination functions can thus be derived. Here, we describe a new gustometer design, successfully used in behavioral experiments, that was guided by our experience with an older version used for over 2 decades. The new computer-controlled gustometer features no dead space in stimulus delivery lines, effective cleaning of the licking substrate, and the ability to measure licking without passing electrical current through the animal. The parts and dimensions are detailed, and the benefits and limitations of certain design features are discussed. Schematics for key circuits are provided as supplemental information. Accordingly, it should be possible to fabricate this device in a fashion customized for one's needs. PMID:25616763

  10. Hepatoprotective effect of aged black garlic extract in rodents.

    PubMed

    Shin, Jung Hyu; Lee, Chang Woo; Oh, Soo Jin; Yun, Jieun; Kang, Moo Rim; Han, Sang-Bae; Park, Heungsik; Jung, Jae Chul; Chung, Yoon Hoo; Kang, Jong Soon

    2014-03-01

    In this study, we investigated the hepatoprotective effects of aged black garlic (ABG) in rodent models of liver injury. ABG inhibited carbon tetrachloride-induced elevation of aspartate transaminase (AST) and alanine transaminase (ALT), which are markers of hepatocellular damage, in SD rats. D-galactosamineinduced hepatocellular damage was also suppressed by ABG treatment. However, ABG does not affect the elevation of alkaline phosphatase (ALP), a marker of hepatobilliary damage, in rats treated with carbon tetrachloride or D-galactosamine. We also examined the effect of ABG on high-fat diet (HFD)-induced fatty liver and subsequent liver damage. ABG had no significant effect on body weight increase and plasma lipid profile in HFD-fed mice. However, HFD-induced increase in AST and ALT, but not ALP, was significantly suppressed by ABG treatment. These results demonstrate that ABG has hepatoprotective effects and suggest that ABG supplementation might be a good adjuvant therapy for the management of liver injury. PMID:24795800

  11. Traumatic Brain Injury Modeling Neuropsychiatric Symptoms in Rodents

    PubMed Central

    Malkesman, Oz; Tucker, Laura B.; Ozl, Jessica; McCabe, Joseph T.

    2013-01-01

    Each year in the US, ?1.5 million people sustain a traumatic brain injury (TBI). Victims of TBI can suffer from chronic post-TBI symptoms, such as sensory and motor deficits, cognitive impairments including problems with memory, learning, and attention, and neuropsychiatric symptoms such as depression, anxiety, irritability, aggression, and suicidal rumination. Although partially associated with the site and severity of injury, the biological mechanisms associated with many of these symptoms and why some patients experience differing assortments of persistent maladies are largely unknown. The use of animal models is a promising strategy for elucidation of the mechanisms of impairment and treatment, and learning, memory, sensory, and motor tests have widespread utility in rodent models of TBI and psychopharmacology. Comparatively, behavioral tests for the evaluation of neuropsychiatric symptomatology are rarely employed in animal models of TBI and, as determined in this review, the results have been inconsistent. Animal behavioral studies contribute to the understanding of the biological mechanisms by which TBI is associated with neurobehavioral symptoms and offer a powerful means for pre-clinical treatment validation. Therefore, further exploration of the utility of animal behavioral tests for the study of injury mechanisms and therapeutic strategies for the alleviation of emotional symptoms are relevant and essential. PMID:24109476

  12. Receptor tyrosine kinase inhibitors in rodent pulmonary hypertension.

    PubMed

    Moreno-Vinasco, Liliana; Garcia, Joe G N

    2010-01-01

    Pulmonary hypertension (PH) is a disorder characterized by vascular remodeling and proliferation, a phenotype dependent upon unimpeded growth factor and kinase pathway activation with strong similarities to malignant tumors. This chapter details our novel application of the multikinase inhibitor, sorafenib, in rodent models of PH to improved hemodynamic parameters and attenuates PH structural changes1. Sorafenib is a Raf kinase inhibitor and our biochemical and genomic evidence supported the potential involvement of the MAPK cascade system and TGFB3 in PH development and the response to therapy. Integration of expression genomic analyses coupled with intense bioinformatics identified gene expression and ontology signatures in the development of PH and implicated the role of cytoskeletal protein such as caldesmon or nmMLCK as potentially key participants in PH-induced vascular remodeling and proliferation. Our studies suggest the PKI sorafenib as a potentially novel treatment for severe PH with the MAPK cascade a potential canonical target profoundly effecting vascular cytoskeletal -rearrangements and remodeling1. PMID:20204746

  13. Protracted brain development in a rodent model of extreme longevity.

    PubMed

    Penz, Orsolya K; Fuzik, Janos; Kurek, Aleksandra B; Romanov, Roman; Larson, John; Park, Thomas J; Harkany, Tibor; Keimpema, Erik

    2015-01-01

    Extreme longevity requires the continuous and large-scale adaptation of organ systems to delay senescence. Naked mole rats are the longest-living rodents, whose nervous system likely undergoes life-long adaptive reorganization. Nevertheless, neither the cellular organization of their cerebral cortex nor indices of structural neuronal plasticity along extreme time-scales have been established. We find that adult neurogenesis and neuronal migration are not unusual in naked mole rat brains. Instead, we show the prolonged expression of structural plasticity markers, many recognized as being developmentally controlled, and multi-year-long postnatal neuromorphogenesis and spatial synapse refinement in hippocampal and olfactory structures of the naked mole rat brain. Neurophysiological studies on identified hippocampal neurons demonstrated that morphological differentiation is disconnected from the control of excitability in all neuronal contingents regardless of their ability to self-renew. Overall, we conclude that naked mole rats show an extremely protracted period of brain maturation that may permit plasticity and resilience to neurodegenerative processes over their decades-long life span. This conclusion is consistent with the hypothesis that naked mole rats are neotenous, with retention of juvenile characteristics to permit survival in a hypoxic environment, with extreme longevity a consequence of greatly retarded development. PMID:26118676

  14. Medial prefrontal cortex role in recognition memory in rodents.

    PubMed

    Morici, Juan Facundo; Bekinschtein, Pedro; Weisstaub, Noelia V

    2015-10-01

    The study of the neurobiology of recognition memory, defined by the integration of the different components of experiences that support recollection of past experiences have been a challenge for memory researches for many years. In the last twenty years, with the development of the spontaneous novel object recognition task and all its variants this has started to change. The features of recognition memory include a particular object or person ("what"), the context in which the experience took place, which can be the arena itself or the location within a particular arena ("where") and the particular time at which the event occurred ("when"). This definition instead of the historical anthropocentric one allows the study of this type of episodic memory in animal models. Some forms of recognition memory that require integration of different features recruit the medial prefrontal cortex. Focusing on findings from spontaneous recognition memory tasks performed by rodents, this review concentrates on the description of previous works that have examined the role that the medial prefrontal cortex has on the different steps of recognition memory. We conclude that this structure, independently of the task used, is required at different memory stages when the task cannot be solved by a single item strategy. PMID:26115848

  15. Development of contrast-enhanced rodent imaging using functional CT

    NASA Astrophysics Data System (ADS)

    Liang, Yun; Stantz, Keith M.; Krishnamurthi, Ganapathy; Steinmetz, Rosemary; Hutchins, Gary D.

    2003-05-01

    Micro-computed tomography (microCT) is capable of obtaining high-resolution images of skeletal tissues. However its image contrast among soft tissues remains inadequate for tumor detection. High speed functional computed tomography will be needed to image tumors by employing x-ray contrast medium. The functional microCT development will not only facilitate the image contrast enhancement among different tissues but also provide information of tumor physiology. To demonstrate the feasibility of functional CT in mouse imaging, sequential computed tomography is performed in mice after contrast material administration using a high-speed clinical CT scanner. Although the resolution of the clinical scanner is not sufficient to dissolve the anatomic details of rodents, bulky physiological parameters in major organs such as liver, kidney, pancreas, and ovaries (testicular) can be examined. For data analysis, a two-compartmental model is employed and implemented to characterize the tissue physiological parameters (regional blood flow, capillary permeability, and relative compartment volumes.) The measured contrast dynamics in kidneys are fitted with the compartmental model to derive the kidney tissue physiology. The study result suggests that it is feasible to extract mouse tissue physiology using functional CT imaging technology.

  16. What Can We Learn from Rodents about Prolactin in Humans?

    PubMed Central

    Ben-Jonathan, Nira; LaPensee, Christopher R.; LaPensee, Elizabeth W.

    2008-01-01

    Prolactin (PRL) is a 23-kDa protein hormone that binds to a single-span membrane receptor, a member of the cytokine receptor superfamily, and exerts its action via several interacting signaling pathways. PRL is a multifunctional hormone that affects multiple reproductive and metabolic functions and is also involved in tumorigenicity. In addition to being a classical pituitary hormone, PRL in humans is produced by many tissues throughout the body where it acts as a cytokine. The objective of this review is to compare and contrast multiple aspects of PRL, from structure to regulation, and from physiology to pathology in rats, mice, and humans. At each juncture, questions are raised whether, or to what extent, data from rodents are relevant to PRL homeostasis in humans. Most current knowledge on PRL has been obtained from studies with rats and, more recently, from the use of transgenic mice. Although this information is indispensable for understanding PRL in human health and disease, there is sufficient disparity in the control of the production, distribution, and physiological functions of PRL among these species to warrant careful and judicial extrapolation to humans. PMID:18057139

  17. Automated tracking of whiskers in videos of head fixed rodents.

    PubMed

    Clack, Nathan G; O'Connor, Daniel H; Huber, Daniel; Petreanu, Leopoldo; Hires, Andrew; Peron, Simon; Svoboda, Karel; Myers, Eugene W

    2012-01-01

    We have developed software for fully automated tracking of vibrissae (whiskers) in high-speed videos (>500 Hz) of head-fixed, behaving rodents trimmed to a single row of whiskers. Performance was assessed against a manually curated dataset consisting of 1.32 million video frames comprising 4.5 million whisker traces. The current implementation detects whiskers with a recall of 99.998% and identifies individual whiskers with 99.997% accuracy. The average processing rate for these images was 8 Mpx/s/cpu (2.6 GHz Intel Core2, 2 GB RAM). This translates to 35 processed frames per second for a 640 px352 px video of 4 whiskers. The speed and accuracy achieved enables quantitative behavioral studies where the analysis of millions of video frames is required. We used the software to analyze the evolving whisking strategies as mice learned a whisker-based detection task over the course of 6 days (8148 trials, 25 million frames) and measure the forces at the sensory follicle that most underlie haptic perception. PMID:22792058

  18. Sexual Differentiation of the Rodent Brain: Dogma and Beyond

    PubMed Central

    Lenz, Kathryn M.; Nugent, Bridget M.; McCarthy, Margaret M.

    2012-01-01

    Steroid hormones of gonadal origin act on the neonatal brain to produce sex differences that underlie adult reproductive physiology and behavior. Neuronal sex differences occur on a variety of levels, including differences in regional volume and/or cell number, morphology, physiology, molecular signaling, and gene expression. In the rodent, many of these sex differences are determined by steroid hormones, particularly estradiol, and are established by diverse downstream effects. One brain region that is potently organized by estradiol is the preoptic area (POA), a region critically involved in many behaviors that show sex differences, including copulatory and maternal behaviors. This review focuses on the POA as a case study exemplifying the depth and breadth of our knowledge as well as the gaps in understanding the mechanisms through which gonadal hormones produce lasting neural and behavioral sex differences. In the POA, multiple cell types, including neurons, astrocytes, and microglia are masculinized by estradiol. Multiple downstream molecular mediators are involved, including prostaglandins, various glutamate receptors, protein kinase A, and several immune signaling molecules. Moreover, emerging evidence indicates epigenetic mechanisms maintain sex differences in the POA that are organized perinatally and thereby produce permanent behavioral changes. We also review emerging strategies to better elucidate the mechanisms through which genetics and epigenetics contribute to brain and behavioral sex differences. PMID:22363256

  19. A New Gustometer for Taste Testing in Rodents

    PubMed Central

    Blonde, Ginger D.; Henderson, Ross P.; Treesukosol, Yada; Hendrick, Paul; Newsome, Ryan; Fletcher, Fred H.; Tang, Te; Donaldson, James A.

    2015-01-01

    In recent years, to circumvent the interpretive limitations associated with intake tests commonly used to assess taste function in rodents, investigators have developed devices called gustometers to deliver small volumes of taste samples and measure immediate responses, thereby increasing confidence that the behavior of the animal is under orosensory control. Most of these gustometers can be used to measure unconditioned licking behavior to stimuli presented for short durations and/or can be used to train the animal to respond to various fluid stimuli differentially so as to obtain a reward and/or avoid punishment. Psychometric sensitivity and discrimination functions can thus be derived. Here, we describe a new gustometer design, successfully used in behavioral experiments, that was guided by our experience with an older version used for over 2 decades. The new computer-controlled gustometer features no dead space in stimulus delivery lines, effective cleaning of the licking substrate, and the ability to measure licking without passing electrical current through the animal. The parts and dimensions are detailed, and the benefits and limitations of certain design features are discussed. Schematics for key circuits are provided as supplemental information. Accordingly, it should be possible to fabricate this device in a fashion customized for one’s needs. PMID:25616763

  20. PhenoWorld: a new paradigm to screen rodent behavior

    PubMed Central

    Castelhano-Carlos, M; Costa, P S; Russig, H; Sousa, N

    2014-01-01

    Modeling depression in animals has inherent complexities that are augmented by intrinsic difficulties to measure the characteristic features of the disorder. Herein, we describe the PhenoWorld (PhW), a new setting in which groups of six rats lived in an ethological enriched environment, and have their feeding, locomotor activity, sleeping and social behavior automatically monitored. A battery of emotional and cognitive tests was used to characterize the behavioral phenotype of animals living in the PhW and in standard conditions (in groups of six and two rats), after exposure to an unpredictable chronic mild stress paradigm (uCMS) and antidepressants. Data reveal that animals living in the PhW displayed similar, but more striking, behavioral differences when exposed to uCMS, such as increased behavioral despair shown in the forced swimming test, resting/sleep behavior disturbances and reduced social interactions. Moreover, several PhW-cage behaviors, such as spontaneous will to go for food or exercise in running wheels, proved to be sensitive indicators of depressive-like behavior. In summary, this new ethological enriched paradigm adds significant discriminative power to screen depressive-like behavior, in particularly rodent's hedonic behavior. PMID:26126181

  1. Electrochemical Techniques for Subsecond Neurotransmitter Detection in Live Rodents

    PubMed Central

    Hascup, Kevin N; Hascup, Erin R

    2014-01-01

    Alterations in neurotransmission have been implicated in numerous neurodegenerative and neuropsychiatric disorders, including Alzheimer disease, Parkinson disease, epilepsy, and schizophrenia. Unfortunately, few techniques support the measurement of real-time changes in neurotransmitter levels over multiple days, as is essential for ethologic and pharmacodynamic testing. Microdialysis is commonly used for these research paradigms, but its poor temporal and spatial resolution make this technique inadequate for measuring the rapid dynamics (milliseconds to seconds) of fast signaling neurotransmitters, such as glutamate and acetylcholine. Enzymatic microelectrode arrays (biosensors) coupled with electrochemical recording techniques have demonstrated fast temporal resolution (less than 1 s), excellent spatial resolution (micron-scale), low detection limits (?200 nM), and minimal damage (50 to 100 m) to surrounding brain tissue. Here we discuss the benefits, methods, and animal welfare considerations of using platinum microelectrodes on a ceramic substrate for enzyme-based electrochemical recording techniques for real-time in vivo neurotransmitter recordings in both anesthetized and awake, freely moving rodents. PMID:25296011

  2. Environmental genotoxicity evaluation using cytogenetic end points in wild rodents.

    PubMed Central

    de Souza Bueno, A M; de Bragana Pereira, C A; Rabello-Gay, M N

    2000-01-01

    We analyzed cytogenetic end points in three populations of two species of wild rodents--Akodon montensis and Oryzomys nigripes--living in an industrial, an agricultural, and a preservation area at the Itaja Valley, state of Santa Catarina, Brazil. Our purpose was to evaluate the performance of the following end points in the establishment of a genotoxic profile of each area: the polychromatic/normochromatic cell ratio; the mitotic index; the frequency of micronucleated cells both in the bone marrow and peripheral blood; and the frequency of cells with chromosome aberrations in the bone marrow. Preparations were obtained using conventional cytogenetic techniques. The results showed a) the role of the end points used as biomarkers in the early detection of genotoxic agents and in the identification of species and populations at higher risk; b) the difference in sensitivity of the species selected as bioindicators in relation to the cytogenetic end points analyzed; c) the need to use at least two sympatric species to detect the presence of genotoxins in each locality; and d) the need to use several end points when trying to establish a genotoxic profile of an area. PMID:11133397

  3. Large-scale functional connectivity networks in the rodent brain.

    PubMed

    Gozzi, Alessandro; Schwarz, Adam J

    2016-02-15

    Resting-state functional Magnetic Resonance Imaging (rsfMRI) of the human brain has revealed multiple large-scale neural networks within a hierarchical and complex structure of coordinated functional activity. These distributed neuroanatomical systems provide a sensitive window on brain function and its disruption in a variety of neuropathological conditions. The study of macroscale intrinsic connectivity networks in preclinical species, where genetic and environmental conditions can be controlled and manipulated with high specificity, offers the opportunity to elucidate the biological determinants of these alterations. While rsfMRI methods are now widely used in human connectivity research, these approaches have only relatively recently been back-translated into laboratory animals. Here we review recent progress in the study of functional connectivity in rodent species, emphasising the ability of this approach to resolve large-scale brain networks that recapitulate neuroanatomical features of known functional systems in the human brain. These include, but are not limited to, a distributed set of regions identified in rats and mice that may represent a putative evolutionary precursor of the human default mode network (DMN). The impact and control of potential experimental and methodological confounds are also critically discussed. Finally, we highlight the enormous potential and some initial application of connectivity mapping in transgenic models as a tool to investigate the neuropathological underpinnings of the large-scale connectional alterations associated with human neuropsychiatric and neurological conditions. We conclude by discussing the translational potential of these methods in basic and applied neuroscience. PMID:26706448

  4. Synthetic cathinones and their rewarding and reinforcing effects in rodents

    PubMed Central

    Watterson, Lucas R.; Olive, M. Foster

    2014-01-01

    Synthetic cathinones, colloquially referred to as bath salts, are derivatives of the psychoactive alkaloid cathinone found in Catha edulis (Khat). Since the mid-to-late 2000s, these amphetamine-like psychostimulants have gained popularity amongst drug users due to their potency, low cost, ease of procurement, and constantly evolving chemical structures. Concomitant with their increased use is the emergence of a growing collection of case reports of bizarre and dangerous behaviors, toxicity to numerous organ systems, and death. However, scientific information regarding the abuse liability of these drugs has been relatively slower to materialize. Recently we have published several studies demonstrating that laboratory rodents will readily self-administer the first generation synthetic cathinones methylenedioxypyrovalerone (MDPV) and methylone via the intravenous route, in patterns similar to those of methamphetamine. Under progressive ratio schedules of reinforcement, the rank order of reinforcing efficacy of these compounds are MDPV ? methamphetamine > methylone. MDPV and methylone, as well as the second generation synthetic cathinones ?-pyrrolidinovalerophenone (?-PVP) and 4-methylethcathinone (4-MEC), also dose-dependently increase brain reward function. Collectively, these findings indicate that synthetic cathinones have a high abuse and addiction potential and underscore the need for future assessment of the extent and duration of neurotoxicity induced by these emerging drugs of abuse. PMID:25328910

  5. Near-infrared light penetration profile in the rodent brain

    PubMed Central

    Abdo, Ammar; Ersen, Ali; Sahin, Mesut

    2013-01-01

    Abstract. Near-infrared (NIR) lasers find applications in neuro-medicine both for diagnostic and treatment purposes. Penetration depth and profile into neural tissue are critical parameters to be considered in these applications. Published data on the optical properties of rodent neural tissue are rare, despite the frequent use of rats as an animal model. The aim of this study was to measure the light intensity profile inside the rat brain using a direct method, while the medium is being illuminated by an NIR laser beam, and compare the results with in vitro measurements of transmittance in the rat brain slices. The intensity profile along the vertical axis had an exponential decline with multiple regions that could be approximated with different coefficients. The Monte Carlo method that was used to simulate lighttissue interactions and predict the scattering coefficient of brain tissue from the measurements suggested that more scattering occurred in deeper layers of the cortex. A single scattering coefficient of 125??cm?1 was estimated for cortical layers from 300 to 1500?m and a gradually increasing value from 125 to 370??cm?1 for depths of 1500 to 3000?m. The deviations of in vivo results from the in vitro transmittance measurements, as well as the postmortem in vivo results from the alive measurements were significant. PMID:23831713

  6. Infracommunity dynamics of chiggers (Trombiculidae) parasitic on a rodent.

    PubMed

    Barnard, Karlien; Krasnov, Boris R; Goff, Lee; Matthee, Sonja

    2015-11-01

    We studied the structure of chigger mite (Trombiculidae) communities parasitic on a South African rodent, Rhabdomys pumilio. We aimed to determine whether: (a) different chigger species differ in preferences for certain body areas of a host and (b) chigger assemblages among body areas of the same host individual, are structured and if so, whether the structure of these assemblages is aggregative or segregative. Rhabdomys pumilio is parasitized by seven chigger species belonging to six genera. The three most abundant species (Leptotrombidium sp. nr. muridium, Schoutedenichia sp. and Neoschoengastia sp. A) displayed a non-random distribution across the host body, with the two most abundant species (L. sp. nr. muridium and Schoutedenichia sp.) significantly associated with the tail area. In addition, whenever non-randomness of chigger co-occurrence in the same body area was recorded, it indicated positive but not negative co-occurrences of different species. This might be due to similarity of chigger species in resource needs and strategies to avoid host defence efforts. PMID:26303191

  7. Hepatoprotective Effect of Aged Black Garlic Extract in Rodents

    PubMed Central

    Lee, Chang Woo; Oh, Soo Jin; Yun, Jieun; Kang, Moo Rim; Han, Sang-Bae; Park, Heungsik; Jung, Jae Chul; Chung, Yoon Hoo; Kang, Jong Soon

    2014-01-01

    In this study, we investigated the hepatoprotective effects of aged black garlic (ABG) in rodent models of liver injury. ABG inhibited carbon tetrachloride-induced elevation of aspartate transaminase (AST) and alanine transaminase (ALT), which are markers of hepatocellular damage, in SD rats. D-galactosamineinduced hepatocellular damage was also suppressed by ABG treatment. However, ABG does not affect the elevation of alkaline phosphatase (ALP), a marker of hepatobilliary damage, in rats treated with carbon tetrachloride or D-galactosamine. We also examined the effect of ABG on high-fat diet (HFD)-induced fatty liver and subsequent liver damage. ABG had no significant effect on body weight increase and plasma lipid profile in HFD-fed mice. However, HFD-induced increase in AST and ALT, but not ALP, was significantly suppressed by ABG treatment. These results demonstrate that ABG has hepatoprotective effects and suggest that ABG supplementation might be a good adjuvant therapy for the management of liver injury. PMID:24795800

  8. Dynamic Resting State Functional Connectivity in Awake and Anesthetized Rodents

    PubMed Central

    Liang, Zhifeng; Liu, Xiao; Zhang, Nanyin

    2014-01-01

    Since its introduction, resting-state functional magnetic resonance imaging (rsfMRI) has been a powerful tool for investigating functional neural networks in both normal and pathological conditions. When measuring resting-state functional connectivity (RSFC), most rsfMRI approaches do not consider its temporal variations and thus only provide the averaged RSFC over the scan time. Recently, there has been a surge of interest to investigate the dynamic characteristics of RSFC in humans, and promising results have been yielded. However, our knowledge regarding the dynamic RSFC in animals remains sparse. In the present study we utilized the single-volume coactivation method to systematically study the dynamic properties of RSFC within the networks of infralimbic cortex (IL) and primary somatosensory cortex (S1) in both awake and anesthetized rats. Our data showed that both IL and S1 networks could be decomposed into several spatially reproducible but temporally changing co-activation patterns (CAPs), suggesting that dynamic RSFC was indeed a characteristic feature in rodents. In addition, we demonstrated that anesthesia profoundly impacted the dynamic RSFC of neural circuits subserving cognitive and emotional functions but had less effects on sensorimotor systems. Finally, we examined the temporal characteristics of each CAP, and found that individual CAPs exhibited consistent temporal evolution patterns. Together, these results suggest that dynamic RSFC might be a general phenomenon in vertebrate animals. In addition, this study has paved the way for further understanding the alterations of dynamic RSFC in animal models of brain disorders. PMID:25315787

  9. Species of Enterococcus faecalis associated with free-living rodents.

    PubMed

    Laukova, A; Strompfova, V; Simonova, M; Styriak, I; Swiecicka, I

    2008-01-01

    Enterococci from different free-living rodents were isolated and selected. The strains were genotyped and their antibiotic sensitivity and /or resistance, production of lactic acid, urease activity, the presence of enterocin structural genes, plasmid detection, and their binding ability to proteins were determined. Among 24 enterococcal strains, 17 strains were allotted to the species Enterococcus faecalis by tDNA-PCR, 7 strains being not yet identified. Only Enterococcus sp. ES66 possessed the structural genes for the production of enterocins (Ent) A and P. E. faecalis EE61 had the gene for EntL50B. The other isolates were Ent-gene-free. Enterococci were mostly sensitive to antibiotic treatment . The plasmid DNA was detected only in the strain EE97. The average value of lactic acid production reached 896 +/- 90 micromol/L. Most of the strains possessed low ureolytic activity. Enterococci bound very well sub-epithelial proteins, reaching the value of 3 by the particle agglutination assay, especially concerning the heparin, bovine lactoferrin and porcine fibronectin. PMID:18837168

  10. Circadian desynchronization triggers premature cellular aging in a diurnal rodent.

    PubMed

    Grosbellet, Edith; Zahn, Sandrine; Arriv, Mathilde; Dumont, Stphanie; Gourmelen, Sylviane; Pvet, Paul; Challet, Etienne; Criscuolo, Franois

    2015-12-01

    Chronic jet lag or shift work is deleterious to human metabolic health, in that such circadian desynchronization is associated with being overweight and the prevalence of altered glucose metabolism. Similar metabolic changes are observed with age, suggesting that chronic jet lag and accelerated cell aging are intimately related, but the association remains to be determined. We addressed whether jet lag induces metabolic and cell aging impairments in young grass rats (2-3 mo old), using control old grass rats (12-18 mo old) as an aging reference. Desynchronized young and control old subjects had impaired glucose tolerance (+60 and +280%) when compared with control young animals. Despite no significant variation in liver DNA damage, shorter telomeres were characterized, not only in old animal liver cells (-18%), but also at an intermediate level in desynchronized young rats (-9%). The same pattern was found for deacetylase sirtuin (SIRT)-1 (-57 and -29%), confirming that jet-lagged young rats have an intermediate aging profile. Our data indicate that an experimental circadian desynchronization in young animals is associated with a precocious aging profile based on 3 well-known markers, as well as a prediabetic phenotype. Such chronic jet lag-induced alterations observed in a diurnal species constitute proof of principle of the need to develop preventive treatments in jet-lagged persons and shift workers.-Grosbellet, E., Zahn, S., Arriv, M., Dumont, S., Gourmelen, S., Pvet, P., Challet, E., Criscuolo, F. Circadian desynchronization triggers premature cellular aging in a diurnal rodent. PMID:26260033

  11. Naturalistic rodent models of chronic early-life stress.

    PubMed

    Molet, Jenny; Maras, Pamela M; Avishai-Eliner, Sarit; Baram, Tallie Z

    2014-12-01

    A close association between early-life experience and cognitive and emotional outcomes is found in humans. In experimental models, early-life experience can directly influence a number of brain functions long-term. Specifically, and often in concert with genetic background, experience regulates structural and functional maturation of brain circuits and alters individual neuronal function via large-scale changes in gene expression. Because adverse experience during sensitive developmental periods is often associated with neuropsychiatric disease, there is an impetus to create realistic models of distinct early-life experiences. These can then be used to study causality between early-life experiential factors and cognitive and emotional outcomes, and to probe the underlying mechanisms. Although chronic early-life stress has been linked to the emergence of emotional and cognitive disorders later in life, most commonly used rodent models of involve daily maternal separation and hence intermittent early-life stress. We describe here a naturalistic and robust chronic early-life stress model that potently influences cognitive and emotional outcomes. Mice and rats undergoing this stress develop structural and functional deficits in a number of limbic-cortical circuits. Whereas overt pathological memory impairments appear during adulthood, emotional and cognitive vulnerabilities emerge already during adolescence. This naturalistic paradigm, widely adopted around the world, significantly enriches the repertoire of experimental tools available for the study of normal brain maturation and of cognitive and stress-related disorders including depression, autism, post-traumatic stress disorder, and dementia. PMID:24910169

  12. Determination of five folate monoglutamates in rodent diets.

    PubMed

    Kiekens, Filip; Daele, Jeroen Van; Blancquaert, Dieter; Van Der Straeten, Dominique; Lambert, Willy E; Stove, Christophe P

    2015-11-18

    A method for the quantitative determination of folates in rodent diets is very important for correct interpretation of folate intake during feeding trials, given the possible discrepancy between the actual folate concentration in the diet and that mentioned on the product sheet. Liquid chromatography tandem-mass spectrometry is the method of choice to differentiate and quantify the individual folate species present. This discrepancy may be accounted for by, e.g., inaccurate folic acid supplementation and/or the presence of endogenous reduced and substituted folates. We developed a method, validated based on FDA guidelines, that allows the measurement of added and endogenous folates by quantitative determination of 5 folate monoglutamates with linear ranges from 8 μg to 2 mg/kg feed. This information, combined with feed intake data, allows insight into the actual folate intake in animal feeding studies. The relevance of this method was illustrated by the analysis of several feed samples of varying composition, by the investigation of the effect of casein incorporation, and by evaluating the variability of the folate content between pellets and production batches. PMID:26501433

  13. Heterochrony and patterns of cranial suture closure in hystricognath rodents

    PubMed Central

    Wilson, Laura A B; Sánchez-Villagra, Marcelo R

    2009-01-01

    Sutures, joints that allow one bone to articulate with another through intervening fibrous connective tissue, serve as major sites of bone expansion during postnatal craniofacial growth in the vertebrate skull and represent an aspect of cranial ontogeny which may exhibit functional and phylogenetic correlates. Suture evolution among hystricognath rodents, an ecologically diverse group represented here by 26 species, is examined using sequence heterochrony methods, i.e. event pairing and parsimov. Although minor nuances in suture closure sequence exist between species, the overall sequence was found to be conserved both across the hystricognath group and, to an increasing degree, within selected clades. At species level, suture closure pattern exhibited a significant positive correlation with patterns previously reported for hominoids. Patterns for most clades revealed the first sutures to close are those contacting the exoccipital, interparietal, and palatine bones. Heterochronic shifts were found along 19 of 35 branches within the hystricognath phylogeny. The number of shifts per node ranged from one to seven events and, overall, involved 21 of 34 suture sites. The topology generated by parsimony analyses of the event pair matrix yielded only one grouping that was congruent with the evolutionary relationships, compiled from morphological and molecular studies, taken as framework. Sutures contacting the exoccipital displayed the highest levels of most complete closure across all species. Level of suture closure is negatively correlated with cranial length (P < 0.05). Differing life history and locomotory strategies are coupled in part with differing suture closure patterns among several species. PMID:19245501

  14. A novel approach to scavenging anesthetic gases in rodent surgery.

    PubMed

    Nesbitt, Jeffrey C; Krageschmidt, Dale A; Blanco, Michael C

    2013-01-01

    Laboratory animal procedures using gas anesthetics may amass elevated waste gas concentrations in operating rooms if controls are not implemented for capturing and removing the vapors. Area sampling using an infrared analyzer indicated isoflurane concentrations likely to exceed occupational exposure guidelines. Our study showed environmental concentrations of oxygen as high as 40% and isoflurane concentrations >100 ppm when no controls or merely passive controls were utilized. These extraneous isoflurane emissions were determined to be originating from the pre-procedural induction process as well as the gas delivery nose cone. A novel waste gas collection cylinder was designed to enclose the gas delivery nose cone and animal head during the administration of anesthetic gases. The vented cylinder utilized a house vacuum to remove the waste anesthetic gases from the surgical field. A commercially available induction chamber designed to be actively and externally exhausted was used to lower concentrations during the induction process. With implementation of local exhaust ventilation controls, waste anesthetic gas concentrations decreased to below recommended occupational exposure levels. In vitro (sham) testing compared favorably to in vivo measurements validating the reduction capability of active ventilation during rodent anesthetic administration. In vivo isoflurane reductions for the induction chamber emissions, the operating room, and the surgeon's breathing zone were 95%, 60%, and 53%, respectively. The same measurements for an in vitro procedure were 98%, 84%, and 87%, respectively. PMID:23915295

  15. Enzymatic activity of rodents acclimated to cold and long scotophase

    NASA Astrophysics Data System (ADS)

    Fourie, F. Le R.; Haim, A.

    1980-09-01

    Rodents representative of a diurnal species ( Rhabdomys pumilio) as well as a nocturnal species ( Praomys natalensis) were acclimated to cold (Ta = 8°C) at a photoperiod of LD 12:12 and a long scotophase (LD 8; 16) at a temperature of 25° C(Ta). Control groups were kept for both species at Ta = 25° C and LD 12:12 and winter acclimated individuals were obtained during July and August to serve as further reference. Blood samples obtained from the tail were analysed for enzymes representative of three major biochemical pathways. The enzymatic activity of LDH (glycolytic pathway), MDH (Krebs cycle) and G6PDH (hexose monophosphate shunt, as an indicator of gonadal activity) were monitored to represent metabolic activity of the respective cycles. Cold acclimated as well as winter acclimatized mice revealed similar enzymatic patterns for both species and significant increases in LDH and MDH were recorded with a concurrent decrease in G6PDH activity. Specimens exposed to long scotophase exhibited similar enzymatic patterns for both species studied, but enzymatic activity was higher than those of cold acclimated individuals. From these results it is concluded that cold as well as long scotophase induce metabolic adaptations through biochemical activity in the experimental animals. The effect of long scotophase is assumed to be an important factor in the induction of winter acclimatization.

  16. In vivo optogenetic stimulation of the rodent central nervous system.

    PubMed

    Sidor, Michelle M; Davidson, Thomas J; Tye, Kay M; Warden, Melissa R; Diesseroth, Karl; McClung, Colleen A

    2015-01-01

    The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution has been a long sought tool for neuroscientists in the systems-level search for the neural circuitry governing complex behavioral states. Optogenetics is a cutting-edge tool that is revolutionizing the field of neuroscience and represents one of the first systematic approaches to enable causal testing regarding the relation between neural signaling events and behavior. By combining optical and genetic approaches, neural signaling can be bi-directionally controlled through expression of light-sensitive ion channels (opsins) in mammalian cells. The current protocol describes delivery of specific wavelengths of light to opsin-expressing cells in deep brain structures of awake, freely-moving rodents for neural circuit modulation. Theoretical principles of light transmission as an experimental consideration are discussed in the context of performing in vivo optogenetic stimulation. The protocol details the design and construction of both simple and complex laser configurations and describes tethering strategies to permit simultaneous stimulation of multiple animals for high-throughput behavioral testing. PMID:25651158

  17. Use of rodents as models of human diseases

    PubMed Central

    Vandamme, Thierry F.

    2014-01-01

    Advances in molecular biology have significantly increased the understanding of the biology of different diseases. However, these discoveries have not yet been fully translated into improved treatments for patients with diseases such as cancers. One of the factors limiting the translation of knowledge from preclinical studies to the clinic has been the limitations of in vivo diseases models. In this brief review, we will discuss the advantages and disadvantages of rodent models that have been developed to simulate human pathologies, focusing in models that employ xenografts and genetic modification. Within the framework of genetically engineered mouse (GEM) models, we will review some of the current genetic strategies for modeling diseases in the mouse and the preclinical studies that have already been undertaken. We will also discuss how recent improvements in imaging technologies may increase the information derived from using these GEMs during early assessments of potential therapeutic pathways. Furthermore, it is interesting to note that one of the values of using a mouse model is the very rapid turnover rate of the animal, going through the process of birth to death in a very short timeframe relative to that of larger mammalian species. PMID:24459397

  18. OCT-aided anastomosis platform study in the rodent model

    NASA Astrophysics Data System (ADS)

    Huang, Yong; Tong, Dedi; Zhu, Shan; Wu, Lehao; Ibrahim, Zuhaib; Lee, WP Andrew; Brandacher, Gerald; Kang, Jin U.

    2014-02-01

    Anastomosis is one of the most commonly performed procedure in the clinical environment that involves tubular structures, such as blood vessel, lymphatic vessel, seminal duct and ureter. Suture based anastomosis is still the foundation for most basic surgical training and clinical operation, although alternate techniques have been developed and under development. For those tubular-structure-anastomosis, immediate real-time post-operative evaluation of the surgical outcome is critical to the success of surgery. Previously evaluation is mostly based on surgeons' experience. Fourier-domain optical coherence tomography is high-speed, high-resolution noninvasive 3D imaging modality that has been widely used in the biomedical research and clinical study. In this study we used Fourier-domain optical coherence tomography as an evaluation tool for anastomosis of lymphatic vessels, ureter and seminal duct in rodent model. Immediate post-operative and long term surgical site data were collected and analyzed. Critical clinical parameters such as lumen patency, anastomosed site narrowing and suture error detection are provided to surgeons.

  19. Effect of predation risk on selectivity in heteromyid rodents.

    PubMed

    Leaver, Lisa A.; Daly, Martin

    2003-08-29

    Variations in predation risk affect the costs of foraging and may therefore warrant different foraging decisions. One class of models ("higher requisite profit") predicts that foragers should become more selective when predation risk increases, as low-profitability items that do not cover the increased costs are dropped from the diet. An alternative class of models ("reduced finickiness") predicts that foragers should become less selective when predation risk increases, because selectivity requires more extensive assessment and/or search behaviour, prolonging exposure to risk. We assessed the selectivity of foraging heteromyid rodents (Merriam's kangaroo rats, Dipodomys merriami, and pocket mice, Chaetodipus spp.) by comparing differences in "giving up densities" (GUD: the quantity of cryptic food left in a patch by animals for whom the diminishing marginal gains from foraging have dropped below the threshold for continued search) for foods of different value as a measure of selectivity in patches varying in predation risk. Data collected over two field seasons revealed that heteromyids were more selective when predation risk was highest; away from the protective cover of shrubs during the full moon. These findings support the predictions of higher requisite profit models. PMID:12914997

  20. The effects of dietary restriction on oxidative stress in rodents

    PubMed Central

    Walsh, Michael E.; Shi, Yun; Van Remmen, Holly

    2013-01-01

    Oxidative stress is observed during aging and in numerous age-related diseases. Dietary restriction (DR) is a regimen that protects against disease and extends lifespan in multiple species. However, it is unknown how DR mediates its protective effects. One prominent and consistent effect of DR in a number of systems is the ability to reduce oxidative stress and damage. The purpose of this review is to comprehensively examine the hypothesis that dietary restriction reduces oxidative stress in rodents by decreasing reactive oxygen species (ROS) production and increasing antioxidant enzyme activity, leading to an overall reduction of oxidative damage to macromolecules. The literature reveals that the effects of DR on oxidative stress are complex and likely influenced by a variety of factors, including sex, species, tissue examined, types of ROS and antioxidant enzymes examined, and duration of DR. Here we present a comprehensive review of the existing literature on the effect of DR on mitochondrial ROS generation, antioxidant enzymes and oxidative damage. In a majority of studies, dietary restriction had little effect on mitochondrial ROS production or antioxidant activity. On the other hand, DR decreased oxidative damage in the majority of cases. Although the effects of DR on endogenous antioxidants are mixed, we find that glutathione levels are the most likely antioxidant to be increased by dietary restriction, which supports the emerging redox-stress hypothesis of aging. PMID:23743291

  1. Protracted brain development in a rodent model of extreme longevity

    PubMed Central

    Penz, Orsolya K.; Fuzik, Janos; Kurek, Aleksandra B.; Romanov, Roman; Larson, John; Park, Thomas J.; Harkany, Tibor; Keimpema, Erik

    2015-01-01

    Extreme longevity requires the continuous and large-scale adaptation of organ systems to delay senescence. Naked mole rats are the longest-living rodents, whose nervous system likely undergoes life-long adaptive reorganization. Nevertheless, neither the cellular organization of their cerebral cortex nor indices of structural neuronal plasticity along extreme time-scales have been established. We find that adult neurogenesis and neuronal migration are not unusual in naked mole rat brains. Instead, we show the prolonged expression of structural plasticity markers, many recognized as being developmentally controlled, and multi-year-long postnatal neuromorphogenesis and spatial synapse refinement in hippocampal and olfactory structures of the naked mole rat brain. Neurophysiological studies on identified hippocampal neurons demonstrated that morphological differentiation is disconnected from the control of excitability in all neuronal contingents regardless of their ability to self-renew. Overall, we conclude that naked mole rats show an extremely protracted period of brain maturation that may permit plasticity and resilience to neurodegenerative processes over their decades-long life span. This conclusion is consistent with the hypothesis that naked mole rats are neotenous, with retention of juvenile characteristics to permit survival in a hypoxic environment, with extreme longevity a consequence of greatly retarded development. PMID:26118676

  2. Synthetic cathinones and their rewarding and reinforcing effects in rodents.

    PubMed

    Watterson, Lucas R; Olive, M Foster

    2014-06-01

    Synthetic cathinones, colloquially referred to as "bath salts", are derivatives of the psychoactive alkaloid cathinone found in Catha edulis (Khat). Since the mid-to-late 2000's, these amphetamine-like psychostimulants have gained popularity amongst drug users due to their potency, low cost, ease of procurement, and constantly evolving chemical structures. Concomitant with their increased use is the emergence of a growing collection of case reports of bizarre and dangerous behaviors, toxicity to numerous organ systems, and death. However, scientific information regarding the abuse liability of these drugs has been relatively slower to materialize. Recently we have published several studies demonstrating that laboratory rodents will readily self-administer the "first generation" synthetic cathinones methylenedioxypyrovalerone (MDPV) and methylone via the intravenous route, in patterns similar to those of methamphetamine. Under progressive ratio schedules of reinforcement, the rank order of reinforcing efficacy of these compounds are MDPV ? methamphetamine > methylone. MDPV and methylone, as well as the "second generation" synthetic cathinones ?-pyrrolidinovalerophenone (?-PVP) and 4-methylethcathinone (4-MEC), also dose-dependently increase brain reward function. Collectively, these findings indicate that synthetic cathinones have a high abuse and addiction potential and underscore the need for future assessment of the extent and duration of neurotoxicity induced by these emerging drugs of abuse. PMID:25328910

  3. Repeated evolution of carnivory among Indo-Australian rodents.

    PubMed

    Rowe, Kevin C; Achmadi, Anang S; Esselstyn, Jacob A

    2016-03-01

    Convergent evolution, often observed in island archipelagos, provides compelling evidence for the importance of natural selection as a generator of species and ecological diversity. The Indo-Australian Archipelago (IAA) is the world's largest island system and encompasses distinct biogeographic units, including the Asian (Sunda) and Australian (Sahul) continental shelves, which together bracket the oceanic archipelagos of the Philippines and Wallacea. Each of these biogeographic units houses numerous endemic rodents in the family Muridae. Carnivorous murids, that is those that feed on animals, have evolved independently in Sunda, Sulawesi (part of Wallacea), the Philippines, and Sahul, but the number of origins of carnivory among IAA murids is unknown. We conducted a comprehensive phylogenetic analysis of carnivorous murids of the IAA, combined with estimates of ancestral states for broad diet categories (herbivore, omnivore, and carnivore) and geographic ranges. These analyses demonstrate that carnivory evolved independently four times after overwater colonization, including in situ origins on the Philippines, Sulawesi, and Sahul. In each biogeographic unit the origin of carnivory was followed by evolution of more specialized carnivorous ecomorphs such as vermivores, insectivores, and amphibious rats. PMID:26826614

  4. Encephalization, neuronal excess, and neuronal index in rodents.

    PubMed

    Herculano-Houzel, Suzana

    2007-10-01

    Encephalization, or brain size larger than expected from body size, has long been considered to correlate with improved cognitive abilities across species and even intelligence. However, it is still unknown what characteristics of relatively large brains underlie their improved functions. Here, it is shown that more encephalized rodent species have the number of neurons expected for their brain size, but a larger number of neurons than expected for their body size. The number of neurons in excess relative to body size might be available for improved associative functions and, thus, be responsible for the cognitive advantage observed in more encephalized animals. It is further proposed that, if such neuronal excess does provide for improved cognitive abilities, then the total number of excess neurons in each species-here dubbed the neuronal index-should be a better indicator of cognitive abilities than the encephalization quotient (EQ). Because the neuronal index is a function of both the number of neurons expected from the size of the body and the absolute number of neurons in the brain, differences in this parameter across species that share similar EQs might explain why these often have different cognitive capabilities, particularly when comparing across mammalian orders. PMID:17847061

  5. Gene expression patterns in a rodent model for depression.

    PubMed

    Lagus, Markus; Gass, Natalia; Saharinen, Juha; Saarela, Janna; Porkka-Heiskanen, Tarja; Paunio, Tiina

    2010-04-01

    Disturbances in sleep are encountered in the majority of patients with depression. To elucidate the possible molecular mechanisms behind this relationship we examined gene expression changes in a rodent model for depression and disturbed sleep. Animals were treated with daily injections of clomipramine in their early infancy, after which gene expression in basal forebrain was examined using Affymetrix Rat 230.2 chips. We tested the levels of both single transcripts and involved pathways, and searched for common nominators (i.e. transcription factors) that could explain these changes. We identified 72 differentially expressed gene transcripts, many of which are involved in epigenetic regulation, such as DNMT2. Analysis of functional pathways revealed statistically significant changes of the biological process of synaptic transmission, the cellular compartment of the synapse and the molecular function of GABA signalling, showing that transcripts with altered expression are functionally related. Finally, promoter analysis of the differentially expressed genes showed a clear enrichment of binding sites for the transcription factor CREB1, a molecule also involved in epigenetic regulation (cAMP response element-binding protein induces histone modifications). These results indicate that CREB1 may constitute one of the major links between disturbed sleep and mood. The results also highlight the molecular mechanisms in the murine clomipramine model, previously shown to be a valid model for depression. PMID:20384783

  6. Evolving communicative complexity: insights from rodents and beyond.

    PubMed

    Pollard, Kimberly A; Blumstein, Daniel T

    2012-07-01

    Social living goes hand in hand with communication, but the details of this relationship are rarely simple. Complex communication may be described by attributes as diverse as a species' entire repertoire, signallers' individualistic signatures, or complex acoustic phenomena within single calls. Similarly, attributes of social complexity are diverse and may include group size, social role diversity, or networks of interactions and relationships. How these different attributes of social and communicative complexity co-evolve is an active question in behavioural ecology. Sciurid rodents (ground squirrels, prairie dogs and marmots) provide an excellent model system for studying these questions. Sciurid studies have found that demographic role complexity predicts alarm call repertoire size, while social group size predicts alarm call individuality. Along with other taxa, sciurids reveal an important insight: different attributes of sociality are linked to different attributes of communication. By breaking social and communicative complexity down to different attributes, focused studies can better untangle the underlying evolutionary relationships and move us closer to a comprehensive theory of how sociality and communication evolve. PMID:22641825

  7. Rehabilitation and plasticity following stroke: Insights from rodent models.

    PubMed

    Caleo, M

    2015-12-17

    Ischemic injuries within the motor cortex result in functional deficits that may profoundly impact activities of daily living in patients. Current rehabilitation protocols achieve only limited recovery of motor abilities. The brain reorganizes spontaneously after injury, and it is believed that appropriately boosting these neuroplastic processes may restore function via recruitment of spared areas and pathways. Here I review studies on circuit reorganization, neuronal and glial plasticity and axonal sprouting following ischemic damage to the forelimb motor cortex, with a particular focus on rodent models. I discuss evidence pointing to compensatory take-over of lost functions by adjacent peri-lesional areas and the role of the contralesional hemisphere in recovery. One key issue is the need to distinguish "true" recovery (i.e. re-establishment of original movement patterns) from compensation in the assessment of post-stroke functional gains. I also consider the effects of physical rehabilitation, including robot-assisted therapy, and the potential mechanisms by which motor training induces recovery. Finally, I describe experimental approaches in which training is coupled with delivery of plasticizing drugs that render the remaining, undamaged pathways more sensitive to experience-dependent modifications. These combinatorial strategies hold promise for the definition of more effective rehabilitation paradigms that can be translated into clinical practice. PMID:26493858

  8. Naturalistic Rodent Models of Chronic Early-Life Stress

    PubMed Central

    Molet, Jenny; Maras, Pamela M.; Avishai-Eliner, Sarit

    2016-01-01

    A close association between early-life experience and cognitive and emotional outcomes is found in humans. In experimental models, early-life experience can directly influence a number of brain functions long-term. Specifically, and often in concert with genetic background, experience regulates structural and functional maturation of brain circuits and alters individual neuronal function via large-scale changes in gene expression. Because adverse experience during sensitive developmental periods is often associated with neuropsychiatric disease, there is an impetus to create realistic models of distinct early-life experiences. These can then be used to study causality between early-life experiential factors and cognitive and emotional outcomes, and to probe the underlying mechanisms. Although chronic early-life stress has been linked to the emergence of emotional and cognitive disorders later in life, most commonly used rodent models of involve daily maternal separation and hence intermittent early-life stress. We describe here a naturalistic and robust chronic early-life stress model that potently influences cognitive and emotional outcomes. Mice and rats undergoing this stress develop structural and functional deficits in a number of limbic-cortical circuits. Whereas overt pathological memory impairments appear during adulthood, emotional and cognitive vulnerabilities emerge already during adolescence. This naturalistic paradigm, widely adopted around the world, significantly enriches the repertoire of experimental tools available for the study of normal brain maturation and of cognitive and stress-related disorders including depression, autism, post-traumatic stress disorder, and dementia. PMID:24910169

  9. Optimality in the zonation of ammonia detoxification in rodent liver.

    PubMed

    Bartl, Martin; Pfaff, Michael; Ghallab, Ahmed; Driesch, Dominik; Henkel, Sebastian G; Hengstler, Jan G; Schuster, Stefan; Kaleta, Christoph; Gebhardt, Rolf; Zellmer, Sebastian; Li, Pu

    2015-11-01

    The rodent liver eliminates toxic ammonia. In mammals, three enzymes (or enzyme systems) are involved in this process: glutaminase, glutamine synthetase and the urea cycle enzymes, represented by carbamoyl phosphate synthetase. The distribution of these enzymes for optimal ammonia detoxification was determined by numerical optimization. This in silico approach predicted that the enzymes have to be zonated in order to achieve maximal removal of toxic ammonia and minimal changes in glutamine concentration. Using 13 compartments, representing hepatocytes, the following predictions were generated: glutamine synthetase is active only within a narrow pericentral zone. Glutaminase and carbamoyl phosphate synthetase are located in the periportal zone in a non-homogeneous distribution. This correlates well with the paradoxical observation that in a first step glutamine-bound ammonia is released (by glutaminase) although one of the functions of the liver is detoxification by ammonia fixation. The in silico approach correctly predicted the in vivo enzyme distributions also for non-physiological conditions (e.g. starvation) and during regeneration after tetrachloromethane (CCl4) intoxication. Metabolite concentrations of glutamine, ammonia and urea in each compartment, representing individual hepatocytes, were predicted. Finally, a sensitivity analysis showed a striking robustness of the results. These bioinformatics predictions were validated experimentally by immunohistochemistry and are supported by the literature. In summary, optimization approaches like the one applied can provide valuable explanations and high-quality predictions for in vivo enzyme and metabolite distributions in tissues and can reveal unknown metabolic functions. PMID:26438405

  10. Fathering in rodents: Neurobiological substrates and consequences for offspring.

    PubMed

    Bales, Karen L; Saltzman, Wendy

    2016-01-01

    This article is part of a Special Issue "Parental Care". Paternal care, though rare among mammals, is routinely displayed by several species of rodents. Here we review the neuroanatomical and hormonal bases of paternal behavior, as well as the behavioral and neuroendocrine consequences of paternal behavior for offspring. Fathering behavior is subserved by many of the same neural substrates which are also involved in maternal behavior (for example, the medial preoptic area of the hypothalamus). While gonadal hormones such as testosterone, estrogen, and progesterone, as well as hypothalamic neuropeptides such as oxytocin and vasopressin, and the pituitary hormone prolactin, are implicated in the activation of paternal behavior, there are significant gaps in our knowledge of their actions, as well as pronounced differences between species. Removal of the father in biparental species has long-lasting effects on behavior, as well as on these same neuroendocrine systems, in offspring. Finally, individual differences in paternal behavior can have similarly long-lasting, if more subtle, effects on offspring behavior. Future studies should examine similar outcome measures in multiple species, including both biparental species and closely related uniparental species. Careful phylogenetic analyses of the neuroendocrine systems presumably important to male parenting, as well as their patterns of gene expression, will also be important in establishing the next generation of hypotheses regarding the regulation of male parenting behavior. PMID:26122293

  11. Mechanisms and chemical induction of aneuploidy in rodent germ cells

    SciTech Connect

    Mailhes, J B; Marchetti, F

    2004-10-15

    The objective of this review is to suggest that the advances being made in our understanding of the molecular events surrounding chromosome segregation in non-mammalian and somatic cell models be considered when designing experiments for studying aneuploidy in mammalian germ cells. Accurate chromosome segregation requires the temporal control and unique interactions among a vast array of proteins and cellular organelles. Abnormal function and temporal disarray among these, and others to be inidentified, biochemical reactions and cellular organelles have the potential for predisposing cells to aneuploidy. Although numerous studies have demonstrated that certain chemicals (mainly those that alter microtubule function) can induce aneuploidy in mammalian germ cells, it seems relevant to point out that such data can be influenced by gender, meiotic stage, and time of cell-fixation post-treatment. Additionally, a consensus has not been reached regarding which of several germ cell aneuploidy assays most accurately reflects the human condition. More recent studies have shown that certain kinase, phosphatase, proteasome, and topoisomerase inhibitors can also induce aneuploidy in rodent germ cells. We suggest that molecular approaches be prudently incorporated into mammalian germ cell aneuploidy research in order to eventually understand the causes and mechanisms of human aneuploidy. Such an enormous undertaking would benefit from collaboration among scientists representing several disciplines.

  12. Transgenic Rodent Assay for Quantifying Male Germ Cell Mutant Frequency

    PubMed Central

    O'Brien, Jason M.; Beal, Marc A.; Gingerich, John D.; Soper, Lynda; Douglas, George R.; Yauk, Carole L.; Marchetti, Francesco

    2014-01-01

    De novo mutations arise mostly in the male germline and may contribute to adverse health outcomes in subsequent generations. Traditional methods for assessing the induction of germ cell mutations require the use of large numbers of animals, making them impractical. As such, germ cell mutagenicity is rarely assessed during chemical testing and risk assessment. Herein, we describe an in vivo male germ cell mutation assay using a transgenic rodent model that is based on a recently approved Organisation for Economic Co-operation and Development (OECD) test guideline. This method uses an in vitro positive selection assay to measure in vivo mutations induced in a transgenic λgt10 vector bearing a reporter gene directly in the germ cells of exposed males. We further describe how the detection of mutations in the transgene recovered from germ cells can be used to characterize the stage-specific sensitivity of the various spermatogenic cell types to mutagen exposure by controlling three experimental parameters: the duration of exposure (administration time), the time between exposure and sample collection (sampling time), and the cell population collected for analysis. Because a large number of germ cells can be assayed from a single male, this method has superior sensitivity compared with traditional methods, requires fewer animals and therefore much less time and resources. PMID:25145276

  13. Segment Specification for the Payload Segment of the Reusable Reentry Satellite: Rodent Module Version

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Reusable Reentry Satellite (RRS) System is composed of the payload segment (PS), vehicle segment (VS), and mission support (MS) segments. This specification establishes the performance, design, development, and test requirements for the RRS Rodent Module (RM).

  14. The helminthic parasites of rodents in Dakahlia Governorate, with reference to their Egyptian helminth fauna.

    PubMed

    el Shazly, A M; Morsy, T A; el Kady, G A; Ragheb, D A; Handousa, A E; Ahmed, M M; Younis, T A; Habib, K S

    1994-08-01

    No doubt, rodents are among the most important reservoirs of zoonotic diseases. This paper aimed to survey the helminth fauna of the different species of rodents in Dakahlia Governorate. Eight species of rodents were encountered in the different centers examined. A total of fifteen species of helminthic parasites were found. They belong to four classes: Trematoda five species: H. heterophyes, H. pumilio, H. yokogawai, S. tridactyla and E. callawayensis, Cestoidea three species: H diminuta, H. nana and T. taeniaeformis, Nematoda six species: A. cantonensis, T. muris, C. hepatica, S. obvelata, S. muris, S. ratti, and Archiacanthocephala one species: M. moniliformis. The medical and/or veterinary importance of these parasites were discussed. It was concluded that rodents are the most serious source of zoonotic parasites. PMID:8077761

  15. Serologic Evidence of Flavivirus Infections in Peridomestic Rodents in Merida, Mexico.

    PubMed

    Cigarroa-Toledo, Nohemi; Talavera-Aguilar, Lourdes G; Baak-Baak, Carlos M; García-Rejón, Julián E; Hernandez-Betancourt, Silvia; Blitvich, Bradley J; Machain-Williams, Carlos

    2016-01-01

    We conducted surveillance for flavivirus infection in peridomestic rodents in Merida, Mexico in 2011-12. We captured 161 rodents inside private residences, using Sherman traps, including 86 house mice (Mus musculus) and 75 black rats (Rattus rattus). Serum from each animal was assayed by plaque reduction neutralization test (PRNT) using two vertebrate-specific flaviviruses (Apoi and Modoc viruses) and five mosquito-borne flaviviruses (dengue 2, dengue 4, St. Louis encephalitis virus, West Nile, and yellow fever viruses). Sixty-one (37.9%) rodents had antibodies that neutralized at least one virus. Prevalences for flaviviruses were 64.0% and 15.1% for black rats and house mice, respectively. None of the PRNT90 titers exceeded 80, and often they were highest for Modoc virus. These data suggest that a subset of rodents had been infected with Modoc virus or a closely related flavivirus that was not included in the PRNT analysis. PMID:26540177

  16. COMPARATIVE MICROARRAY EXPRESSION ANALYSIS OF SELECTED CANCER RELEVANT GENES IN HYPERTENSIVE RESISTANT VERSUS SUSCEPTIBLE RODENT STRAINS

    EPA Science Inventory

    Hypertension and cancer are prevalent diseases. Epidemiological studies suggest that hypertension may increase the long term risk of cancer. Identification of resistance and/or susceptibility genes using rodent models could provide important insights into the management and treat...

  17. PREDICTING RODENT CARCINOGENICITY OF HALOGENATED HYDROCARBON BY IN VIVO BIOCHEMICAL PARAMETERS

    EPA Science Inventory

    Forty halogenated hydrocarbons of known rodent carcinogenicity (24 carcinogens, 16 noncarcinogens), including many promoters of carcinogenesis, nongenotoxic carcinogens and hepatocarcinogens were selected for study. he effects of these 40 chemicals on four biochemical assays (hep...

  18. Mutualistic interactions between granivorous heteromyid rodents and a preferred food resource, Indian ricegrass (Achnatherum hymenoides)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Granivorous heteromyid rodent species and Indian ricegrass (Achnatherum hymenoides) are both widely distributed throughout North American deserts. The vast majority (~95%) of Indian ricegrass seedling recruitment occurs from seed clusters cached in shallowly-buried scatterhoards by heteromyids, espe...

  19. Factors influencing repeated seed movements by scatter-hoarding rodents in an alpine forest

    PubMed Central

    Wang, Bo; Chen, Jin; Corlett, Richard T.

    2014-01-01

    Scatter-hoarding rodents are effective dispersal agents for many plant species. Several studies have shown that rodents repeatedly re-cache seeds. The re-caching process often has a significant impact on final seedling establishment, but the factors determining its occurrence are poorly understood. In this study, we followed the fate of 3564 artificial seeds that varied in size, nutrient content and tannin content. Seeds cached closer to their original releasing plots were more likely to be re-cached, and to a further distance. Larger seeds were more likely to be re-cached than smaller ones, while nutrient and tannin content had little effect. Most plant species that depend on scatter-hoarding rodents for seed dispersal bear relatively large seeds, and large seeds are usually more likely to be dispersed and to establish seedlings, suggesting that the caching preferences of scatter-hoarding rodents may have played an important role in the evolution of large seeds. PMID:24759374

  20. TROPICAL SPIDERWORT STEM DESICCATION AND RECOVERY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropical spiderwort has the curious ability to survive periods of drought stress, even as segmented pieces of stem. The purpose of this study was to establish the moisture level to which stems of tropical spiderwort (TSW) must desiccate in order to effectively kill the plant regenerative process. ...

  1. Genomics of Tropical Fruit Tree Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genetic improvement of tropical fruit trees is limited when compared to progress achieved in temperate fruit trees and annual crops. Tropical fruit tree breeding programs require significant resources to develop new cultivars that are adapted to modern shipping and storage requirements. The use...

  2. TROPICAL MASS EXTINCTIONS AND THE SCIENTIFIC METHOD

    EPA Science Inventory

    Kangas (1992), Undiscovered species and the falsifiability of the tropical mass extinction hypotheses, ESA Bulletin 73:124-125, 1992, argues that there is a paradox concerning the mass extinctions projected from current rates of tropical deforestation. he parameters; for a given ...

  3. TROPICAL SPIDERWORT SEEDBANK DYNAMICS AND LONGEVITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropical species are often expected to have short seedbank longevity and fairly predictable seedbank dynamics. This is not the case for tropical spiderwort (also known as Benghal dayflower, Commelina benghalensis L.). Although seedbanks near the surface appear to germinate rapidly successively dep...

  4. Use of tropical maize for bioethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropical maize is an alternative energy crop being considered as a feedstock for bioethanol production in the North Central and Midwest United States. Tropical maize is advantageous because it produces large amounts of soluble sugars in its stalks, creates a large amount of biomass, and requires lo...

  5. Zinc requirements of tropical legume cover crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropical soils are deficient in essential plant nutrients, including zinc (Zn). Using cover crops in cropping systems is an important option to improve soil fertility for sustainable crop production. However, success of cover crops in highly weathered tropical infertile acid soils is greatly influen...

  6. Tropical Forests. Global Issues Education Packet.

    ERIC Educational Resources Information Center

    Holm, Amy E.

    Tropical forests provide the world with many products and an incredible diversity of plant and animal life. These forests also provide watershed areas, soil control, climate regulation, and winter homes for migrating birds from North America. It is believed that about 40% of tropical forests have already been destroyed in the last 20-30 years,…

  7. Tropical Forests. Global Issues Education Packet.

    ERIC Educational Resources Information Center

    Holm, Amy E.

    Tropical forests provide the world with many products and an incredible diversity of plant and animal life. These forests also provide watershed areas, soil control, climate regulation, and winter homes for migrating birds from North America. It is believed that about 40% of tropical forests have already been destroyed in the last 20-30 years,

  8. Distinct Leishmania Species Infecting Wild Caviomorph Rodents (Rodentia: Hystricognathi) from Brazil

    PubMed Central

    Cssia-Pires, Renata; Boit, Mariana C.; D'Andrea, Paulo S.; Herrera, Heitor M.; Cupolillo, Elisa; Jansen, Ana Maria; Roque, Andr Luiz R.

    2014-01-01

    Background Caviomorph rodents, some of the oldest Leishmania spp. hosts, are widely dispersed in Brazil. Despite both experimental and field studies having suggested that these rodents are potential reservoirs of Leishmania parasites, not more than 88 specimens were analyzed in the few studies of natural infection. Our hypothesis was that caviomorph rodents are inserted in the transmission cycles of Leishmania in different regions, more so than is currently recognized. Methodology We investigated the Leishmania infection in spleen fragments of 373 caviomorph rodents from 20 different species collected in five Brazilian biomes in a period of 13 years. PCR reactions targeting kDNA of Leishmania sp. were used to diagnose infection, while Leishmania species identification was performed by DNA sequencing of the amplified products obtained in the HSP70 (234) targeting. Serology by IFAT was performed on the available serum of these rodents. Principal findings In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum. These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil. From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting. Conclusions/Significance The infection rate demonstrated by the serology (51.3%) points out that the natural Leishmania infection in caviomorph rodents is much higher than that observed in the molecular diagnosis (4.6%), highlighting that, in terms of the host species responsible for maintaining Leishmania species in the wild, our current knowledge represents only the tip of the iceberg. PMID:25503973

  9. Adaptation for rodent pollination in Leucospermum arenarium (Proteaceae) despite rapid pollen loss during grooming

    PubMed Central

    Johnson, Christopher Michael; Pauw, Anton

    2014-01-01

    Background and Aims Plants are adapted for rodent pollination in diverse and intricate ways. This study explores an extraordinary example of these adaptations in the pincushion Leucospermum arenarium (Proteaceae) from South Africa. Methods Live trapping and differential exclusion experiments were used to test the role of rodents versus birds and insects as pollinators. To explore the adaptive significance of geoflory, inflorescences were raised above ground level and seed production was compared. Captive rodents and flowers with artificial stigmas were used to test the effect of grooming on the rate of pollen loss. Microscopy, nectar composition analysis and manipulative experiments were used to investigate the bizarre nectar production and transport system. Key Results Differential exclusion of rodents, birds and insects demonstrated the importance of rodents in promoting seed production. Live trapping revealed that hairy-footed gerbils, Gerbillurus paeba, and striped field mice, Rhabdomys pumilio, both carried L. arenarium pollen on their forehead and rostrum, but much larger quantities ended up in faeces as a result of grooming. Terrarium experiments showed that grooming exponentially diminished the pollen loads that they carried. The nectar of L. arenarium was found to be unusually viscous and to be presented in a novel location on the petal tips, where rodents could access it without destroying the flowers. Nectar was produced inside the perianth, but was translocated to the petal tips via capillary ducts. In common with many other rodent-pollinated plants, the flowers are presented at ground level, but when raised to higher positions seed production was not reduced, indicating that selection through female function does not drive the evolution of geoflory. Conclusions Despite the apparent cost of pollen lost to grooming, L. arenarium has evolved remarkable adaptations for rodent pollination and provides the first case of this pollination system in the genus. PMID:24607723

  10. Prevalence of Toxoplasma gondii among West African rodent, Thryonomys swinderianus from the Niger Delta.

    PubMed

    Arene, F O

    1986-01-01

    The prevalence of Toxoplasma gondii among West African rodent, Thryonomys swinderianus, was assessed by the Sabin-Feldman dye-test. All of the 104 animals examined in the study were seropositive for Toxoplasma dye-test antibody. This indicates that there exists among these rodents a considerable reservoir of Toxoplasma from which infection can be transmitted to man and other animal species in that area. PMID:3722813

  11. Experimental evaluation of rodent exclusion methods to reduce hantavirus transmission to humans in rural housing.

    PubMed

    Glass, G E; Johnson, J S; Hodenbach, G A; Disalvo, C L; Peters, C J; Childs, J E; Mills, J N

    1997-04-01

    An experimental assessment of methods to reduce rodent infestations in rural housing was conducted in Yosemite National Park, California, Sequoia/Kings Canyon National Parks, California, and Shenandoah National Park, Virginia. During pretreatment surveys, nearly all (63 of 68) selected units had past or ongoing rodent activity inside. Active infestations were found in 58.8% of the units. Peromyscus spp. represented 91.2% of all animals caught inside housing units. Despite little harborage, rodent activity was common near housing (290 animals/2,254 trap nights). The most common species present was Peromyscus maniculatus (43-50% of all captures). This species was especially frequent (49-87% of Peromyscus captures) around the foundations of housing units. Habitat had little effect on captures. There were 1.8 Peromyscus caught per unit along the foundations of housing in modified rural settings with grass lawns compared with 1.2 Peromyscus caught per unit in sites located in mature woodlands. During autumn of 1994, randomly selected housing units were rodent proofed by sealing openings associated with chases, roof eaves, and attics with insulation and wire mesh. Housing was examined and the fauna was resampled in the spring-summer of 1995. Rodent-proofed houses were infested significantly less often (3 of 28) than control houses (13 of 36) (P = 0.02) and the intensity of infestation was lower in experimental houses (6 versus 23 mice/treatment). More than 25% of the mice trapped inside the houses had been marked outside the houses during the three-day surveys, demonstrating movement of mice adjacent to the buildings into not rodent-proofed housing. As in the previous autumn, most of the animals captured in (98.9%) and along the foundations of the houses (77.5%) were Peromyscus spp. These results demonstrate that Peromyscus frequently invade rural housing but rodent-proofing effectively eliminates or substantially reduces rodent activity. PMID:9158040

  12. Simulation of Tropical Biomass Burning

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Guo, Zitian

    1998-01-01

    The work proposed was carried out as planned. The work described in this final report formed the basis for a follow-on research grant research grant from NASA Ames Research Center. The research objectives that were achieved during the course of our studies include the following: (1) the evaluation of several components of MM5 (Meteorological Model 5 version 2) and the Global/Regional Atmospheric Chemistry Event Simulator (GRACES) combined modeling system; (2) improved calculations of the transport of tracers for both NASA airborne missions, Study of Ozone and Nitrogen oxides experiment (SONEX) and Pacific Exploratory MIssion in the Tropics (PEM-Tropics); (3) improved source strength estimates for isoprene, dust and similar emissions from the Earth's surface. This required the use of newly available databases on the Earth's surface and vegetation; (4) completed atmospheric chemistry simulations of radicals and nitrogen oxide species; (5)improved the handling of cumulonimbus convection by modifying the existing scheme; (6) identified the role of the African Intertropical Front, using MM5's nesting capability to refine model resolution in crucial areas; modified the MM5 trajectory program to allow it to work much better for a parcel crossing the west/east boundaries.

  13. Mission Investigates Tropical Cirrus Clouds

    NASA Astrophysics Data System (ADS)

    Jenson, Eric; Starr, David; Toon, Owen B.

    2004-02-01

    It has been a year since NASA conducted the highly successful Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment Study (CRYSTAL-FACE). The measurement campaign was designed to investigate the physical properties and formation processes of tropical cirrus clouds. CRYSTAL-FACE was sponsored by NASA's Earth Science Enterprise as an integral component of its Earth observation research strategy, and included substantial collaboration with the National Oceanic and Atmospheric Administration, the National Science Foundation, the Department of Energy, and the Naval Research Laboratory. During July 2002, the mission's six aircraft (NASA ER-2, NASA WB-57, Scaled Composites Proteus, University of North Dakota Citation, NSF-supported NRL P-3, and NRL Twin Otter) operated from the Key West Naval Air Facility. In addition, ground sites were located at the Tamiami airport on the east coast of Florida and near Everglades City on the west coast of Florida. Aircraft and ground site measurements are listed in Table 1. Data archiving is complete, and the data are now available to the general scientific community. Detailed instrument descriptions as well as the final data can be found on the CRYSTAL-FACE Web site (http://cloud1.arc.nasa.gov/crystalface/).

  14. Bridges to sustainable tropical health

    PubMed Central

    Singer, Burton H.; de Castro, Marcia Caldas

    2007-01-01

    Ensuring sustainable health in the tropics will require bridge building between communities that currently have a limited track record of interaction. It will also require new organizational innovation if much of the negative health consequences of large-scale economic development projects are to be equitably mitigated, if not prevented. We focus attention on three specific contexts: (i) forging linkages between the engineering and health communities to implement clean water and sanitation on a broad scale to prevent reworming, after the current deworming-only programs, of people by diverse intestinal parasites; (ii) building integrated human and animal disease surveillance infrastructure and technical capacity in tropical countries on the reporting and scientific evidence requirements of the sanitary and phytosanitary agreement under the World Trade Organization; and (iii) developing an independent and equitable organizational structure for health impact assessments as well as monitoring and mitigation of health consequences of economic development projects. Effective global disease surveillance and timely early warning of new outbreaks will require a far closer integration of veterinary and human medicine than heretofore. Many of the necessary surveillance components exist within separate animal- and human-oriented organizations. The challenge is to build the necessary bridges between them. PMID:17913894

  15. Indirect food web interactions mediated by predator-rodent dynamics: relative roles of lemmings and voles.

    PubMed

    Ims, Rolf A; Henden, John-Andr; Thingnes, Anders V; Killengreen, Siw T

    2013-01-01

    Production cycles in birds are proposed as prime cases of indirect interactions in food webs. They are thought to be driven by predators switching from rodents to bird nests in the crash phase of rodent population cycles. Although rodent cycles are geographically widespread and found in different rodent taxa, bird production cycles appear to be most profound in the high Arctic where lemmings dominate. We hypothesized that this may be due to arctic lemmings inducing stronger predator responses than boreal voles. We tested this hypothesis by estimating predation rates in dummy bird nests during a rodent cycle in low-Arctic tundra. Here, the rodent community consists of a spatially variable mix of one lemming (Lemmus lemmus) and two vole species (Myodes rufocanus and Microtus oeconomus) with similar abundances. In consistence with our hypothesis, lemming peak abundances predicted well crash-phase nest predation rates, whereas the vole abundances had no predictive ability. Corvids were found to be the most important nest predators. Lemmings appear to be accessible to the whole predator community which makes them particularly powerful drivers of food web dynamics. PMID:24173526

  16. Zoonotic Bartonella species in wild rodents in the state of Mato Grosso do Sul, Brazil.

    PubMed

    Favacho, Alexsandra Rodrigues de Mendonça; Andrade, Marcelle Novaes; de Oliveira, Renata Carvalho; Bonvicino, Cibele Rodrigues; D'Andrea, Paulo Sergio; de Lemos, Elba Regina Sampaio

    2015-01-01

    Several rodent-associated Bartonella species cause disease in humans but little is known about their epidemiology in Brazil. The presence of Bartonella spp. in wild rodents captured in two municipalities of the Mato Grosso do Sul state was assessed by polymerase chain reaction (PCR). Fragments of heart tissue from 42 wild rodents were tested using primers targeting the Bartonella 16S-23S intergenic transcribed spacer (ITS) region and citrate synthase gltA gene. The wild rodents were identified based on external and cranial morphology and confirmed at species level by mitochondrial DNA (cytochrome B) sequencing and karyotype. Overall, 42.9% (18/42) of the wild rodents were PCR positive for Bartonella spp.: Callomys callosus (04), Cerradomys maracajuensis (04), Hylaeamus megacephalus (01), Necromys lasiurus (06), Nectomys squamipes (01), Oecomys catherinae (01) and Oxymycterus delator (01). Bartonella vinsonii subsp. arupensis was detected in N. lasiurus (46%) and C. callosus (21%) captured in the two study sites. We reported the first molecular detection of B. vinsonii subsp. arupensis in different species of wild rodents collected in the Brazilian territory. Further studies are needed to examine the role of these mammals in the eco-epidemiology of bartonellosis in Brazil. PMID:26344604

  17. Middle Eocene rodents from Peruvian Amazonia reveal the pattern and timing of caviomorph origins and biogeography

    PubMed Central

    Antoine, Pierre-Olivier; Marivaux, Laurent; Croft, Darin A.; Billet, Guillaume; Ganerd, Morgan; Jaramillo, Carlos; Martin, Thomas; Orliac, Mava J.; Tejada, Julia; Altamirano, Ali J.; Duranthon, Francis; Fanjat, Grgory; Rousse, Sonia; Gismondi, Rodolfo Salas

    2012-01-01

    The long-term isolation of South America during most of the Cenozoic produced a highly peculiar terrestrial vertebrate biota, with a wide array of mammal groups, among which caviomorph rodents and platyrrhine primates are Mid-Cenozoic immigrants. In the absence of indisputable pre-Oligocene South American rodents or primates, the mode, timing and biogeography of these extraordinary dispersals remained debated. Here, we describe South America's oldest known rodents, based on a new diverse caviomorph assemblage from the late Middle Eocene (approx. 41 Ma) of Peru, including five small rodents with three stem caviomorphs. Instead of being tied to the Eocene/Oligocene global cooling and drying episode (approx. 34 Ma), as previously considered, the arrival of caviomorphs and their initial radiation in South America probably occurred under much warmer and wetter conditions, around the Mid-Eocene Climatic Optimum. Our phylogenetic results reaffirm the African origin of South American rodents and support a trans-Atlantic dispersal of these mammals during Middle Eocene times. This discovery further extends the gap (approx. 15 Myr) between first appearances of rodents and primates in South America. PMID:21993503

  18. Indirect food web interactions mediated by predator–rodent dynamics: relative roles of lemmings and voles

    PubMed Central

    Ims, Rolf A.; Henden, John-André; Thingnes, Anders V.; Killengreen, Siw T.

    2013-01-01

    Production cycles in birds are proposed as prime cases of indirect interactions in food webs. They are thought to be driven by predators switching from rodents to bird nests in the crash phase of rodent population cycles. Although rodent cycles are geographically widespread and found in different rodent taxa, bird production cycles appear to be most profound in the high Arctic where lemmings dominate. We hypothesized that this may be due to arctic lemmings inducing stronger predator responses than boreal voles. We tested this hypothesis by estimating predation rates in dummy bird nests during a rodent cycle in low-Arctic tundra. Here, the rodent community consists of a spatially variable mix of one lemming (Lemmus lemmus) and two vole species (Myodes rufocanus and Microtus oeconomus) with similar abundances. In consistence with our hypothesis, lemming peak abundances predicted well crash-phase nest predation rates, whereas the vole abundances had no predictive ability. Corvids were found to be the most important nest predators. Lemmings appear to be accessible to the whole predator community which makes them particularly powerful drivers of food web dynamics. PMID:24173526

  19. A comparison of bats and rodents as reservoirs of zoonotic viruses: are bats special?

    USGS Publications Warehouse

    Luis, Angela D.; Hayman, David T.S.; O'Shea, Thomas J.; Cryan, Paul M.; Gilbert, Amy T.; Pulliam, Juliet R.C.; Mills, James N.; Timonin, Mary E.; Willis, Craig K.R.; Cunningham, Andrew A.; Fooks, Anthony R.; Rupprecht, Charles E.; Wood, James L.N.; Webb, Colleen T.

    2013-01-01

    Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs.

  20. Leishmania infantum in wild rodents: reservoirs or just irrelevant incidental hosts?

    PubMed

    Navea-Pérez, H M; Díaz-Sáez, V; Corpas-López, V; Merino-Espinosa, G; Morillas-Márquez, F; Martín-Sánchez, J

    2015-06-01

    Wild rodents constitute a very large biomass of potential reservoirs for Leishmania spp. Therefore, an epidemiological study was carried out in a well-known focus of canine leishmaniasis from southern Spain, with the objective of detecting and characterizing Leishmania infantum infection in wild rodents. Blood, liver, spleen, bone marrow, and skin from 37 rodents (24 Apodemus sylvaticus, 9 Rattus rattus, and 4 Mus musculus) were analyzed by optical microscopy, culture, and two different polymerase chain reactions. L. infantum DNA was found in 27% (10 out of 37) of the trapped rodents, in a variety of tissues: bone marrow, spleen, or healthy skin (ear lobe). High prevalences of L. infantum infection were found in the three investigated rodent species. The presence of other trypanosomatids was also evidenced. These rodent species are abundant, widely distributed in Europe, and have a long enough lifespan to overcome the low sandfly activity season. They live in a suitable habitat for sandflies and serve as blood sources for these insects, which can become infected when induced to feed on Leishmania-infected animals. Whether they are reservoirs or just irrelevant incidental hosts, it is clear that the epidemiology of L. infantum is more complex than previously thought, and so is its control. The classic epidemiological cycle dog-sandfly-human is turning into a network of animal species that collaborate with the dog in the maintenance of the parasite under natural conditions and probably showing local differences. PMID:25797596

  1. A comparison of bats and rodents as reservoirs of zoonotic viruses: are bats special?

    PubMed Central

    Luis, Angela D.; Hayman, David T. S.; O'Shea, Thomas J.; Cryan, Paul M.; Gilbert, Amy T.; Pulliam, Juliet R. C.; Mills, James N.; Timonin, Mary E.; Willis, Craig K. R.; Cunningham, Andrew A.; Fooks, Anthony R.; Rupprecht, Charles E.; Wood, James L. N.; Webb, Colleen T.

    2013-01-01

    Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs. PMID:23378666

  2. Joshua tree (Yucca brevifolia) seeds are dispersed by seed-caching rodents

    USGS Publications Warehouse

    Vander Wall, S. B.; Esque, T.; Haines, D.; Garnett, M.; Waitman, B.A.

    2006-01-01

    Joshua tree (Yucca brevifolia) is a distinctive and charismatic plant of the Mojave Desert. Although floral biology and seed production of Joshua tree and other yuccas are well understood, the fate of Joshua tree seeds has never been studied. We tested the hypothesis that Joshua tree seeds are dispersed by seed-caching rodents. We radioactively labelled Joshua tree seeds and followed their fates at five source plants in Potosi Wash, Clark County, Nevada, USA. Rodents made a mean of 30.6 caches, usually within 30 m of the base of source plants. Caches contained a mean of 5.2 seeds buried 3-30 nun deep. A variety of rodent species appears to have prepared the caches. Three of the 836 Joshua tree seeds (0.4%) cached germinated the following spring. Seed germination using rodent exclosures was nearly 15%. More than 82% of seeds in open plots were removed by granivores, and neither microsite nor supplemental water significantly affected germination. Joshua tree produces seeds in indehiscent pods or capsules, which rodents dismantle to harvest seeds. Because there is no other known means of seed dispersal, it is possible that the Joshua tree-rodent seed dispersal interaction is an obligate mutualism for the plant.

  3. Bartonella Genotypes in Fleas (Insecta: Siphonaptera) Collected from Rodents in the Negev Desert, Israel?

    PubMed Central

    Morick, Danny; Krasnov, Boris R.; Khokhlova, Irina S.; Shenbrot, Georgy I.; Kosoy, Michael Y.; Harrus, Shimon

    2010-01-01

    Fleas collected from rodents in the Negev Desert in southern Israel were molecularly screened for Bartonella species. A total of 1,148 fleas, collected from 122 rodents belonging to six species, were pooled in 245 pools based on flea species, sex, and rodent host species. Two Bartonella gene fragments, corresponding to RNA polymerase B (rpoB) and citrate synthase (gltA), were targeted, and 94 and 74 flea pools were found positive by PCR, respectively. The Bartonella 16S-23S internal transcribed spacer (ITS) region was also targeted, and 66 flea pools were found to be positive by PCR. Sixteen different Bartonella gltA genotypes were detected in 94 positive flea pools collected from 5 different rodent species, indicating that fleas collected from each rodent species can harbor several Bartonella genotypes. Based on gltA analysis, identified Bartonella genotypes were highly similar or identical to strains previously detected in rodent species from different parts of the world. A gltA fragment 100% similar to Bartonella henselae was detected in one flea pool. Another 2 flea pools contained gltA fragments that were closely related to B. henselae (98% similarity). The high sequence similarities to the zoonotic pathogen B. henselae warrant further investigation. PMID:20802081

  4. Oxidative and nutrient stability of a standard rodent spaceflight diet during long-term storage.

    PubMed

    Sun, Gwo-Shing; Tou, Janet C; Reiss-Bubenheim, Debra A; Hill, Esther L; Liittschwager, Kurt W; Girten, Beverly E; Pena-Yewkukhiw, Eugenia

    2012-09-01

    The National Aeronautics and Space Administration's standard spaceflight diet for rodents is the nutrient-upgraded rodent food bar (NuRFB). The shelf life of the NuRFB needs to be determined in order to avoid malnutrition of rodents and confounding of research results resulting from nutritional deficiency. The authors compared the oxidative and nutrient stability of NuRFBs stored at either ambient temperature (26 C) or at refrigeration temperature (4 C) for use in long-term rodent feeding experiments. After 0, 3, 6, 9 and 12 months (mo) of storage, lipid oxidation, fatty acid composition and amounts of specific vitamins and amino acids in NuRFBs were analyzed. No oxidative rancidity developed in NuRFBs stored at 4 C for up to 12 mo, but NuRFBs stored at 26 C for 6 mo developed oxidative rancidity and had reduced amounts of ?-linolenic acid (18:3n-6). Despite loss of vitamin E, vitamin A and thiamin after storage at 26 C for 12 mo, vitamin levels in NuRFBs remained at or above the levels recommended for optimal rodent health. The amino acid profile of NuRFBs was unaffected by storage at 4 C or 26 C for 12 mo. The results suggest that NuRFBs stored at 4 C for up to 12 mo and NuRFBs stored at 26 C for up to 6 mo provide suitable nutrition for rodents in long-term experiments. PMID:22914028

  5. Diversity of Enterocytozoon bieneusi genotypes among small rodents in southwestern Poland.

    PubMed

    Perec-Matysiak, Agnieszka; Bu?kowska-Gawlik, Katarzyna; Kv?, Martin; Sak, Bohumil; Hildebrand, Joanna; Le?nia?ska, Kinga

    2015-12-15

    Diversity of Enterocytozoon bieneusi genotypes in wild small rodent populations still remains incomplete and only few molecular studies have been conducted among these hosts. Therefore, the aim of this study was to determine whether small rodents, i.e., Apodemus agrarius, Apodemus flavicollis, Mus musculus and Myodes glareolus act as hosts of E. bieneusi and can play an important role in spore spreading in the environment of south-western Poland. Molecular analyses were conducted to determine pathogen genotypes. A total of 191 fecal and 251 spleen samples collected from 311 rodent individuals were examined for the occurrence of E. bieneusi by PCR amplifying ITS gene. The overall prevalence of E. bieneusi in rodent samples was 38.9%. The nucleotide sequences of ITS region of E. bieneusi revealed the presence a total of 12 genotypes with two being already known, i.e., D and gorilla 1 genotypes. The remaining ten are novel genotypes (WR1-WR10) which segregated into three groups in a neighbor joining phylogeny. This study reports for the first time E. bieneusi occurrence in wild living rodents in Poland and shows extensive genetic diversity within E. bieneusi isolates of rodent origin. PMID:26520234

  6. Hantavirus pulmonary syndrome and rodent reservoirs in the savanna-like biome of Brazil's southeastern region.

    PubMed

    Limongi, J E; Oliveira, R C; Guterres, A; Costa Neto, S F; Fernandes, J; Vicente, L H B; Coelho, M G; Ramos, V N; Ferreira, M S; Bonvicino, C R; D'Andrea, P S; Lemos, E R S

    2016-04-01

    This paper describes the diversity of rodent fauna in an area endemic for hantavirus cardiopulmonary syndrome (HCPS) in Brazil, the population dynamics and the relationship of rodents with hantavirus in the Cerrado (savanna-like) biome. Additionally, an analysis is made of the partial S segment sequences of the hantaviruses obtained from serologically confirmed human HCPS cases and from rodent specimens. Rodents were collected during four campaigns. Human serum samples were collected from suspected cases of HCPS at hospitals in the state of Minas Gerais. The samples antibody-reactive by ELISA were processed by RT-PCR. The PCR product was amplified and sequenced. Hantavirus was detected only in Necromys lasiurus, the wild rodent species most prevalent in the Cerrado biome (min-max: 50-83·7%). All the six human serum samples were hantavirus seropositive and five showed amplified PCR products. The analysis of the nucleotide sequences showed the circulation of a single genotype, the Araraquara hantavirus. The environmental changes that have occurred in the Cerrado biome in recent decades have favoured N. lasiurus in interspecific competition of habitats, thus increasing the risk of contact between humans and rodent species infected with hantavirus. Our data corroborate the definition of N. lasiurus as the main hantavirus reservoir in the Cerrado biome. PMID:26541807

  7. Field efficacy of deltamethrin for rodent flea control in San Bernardino County, California, USA.

    PubMed

    Mian, Lal S; Hitchcock, James C; Madon, Minoo B; Myers, Charles M

    2004-12-01

    A study was conducted to determine the initial and residual activity of deltamethrin (0.05% dust) applied to rodent burrows (at approximately 14 g/burrow) against fleas in the Silverwood Lake area of San Bernardino County. In initial toxicity (2-d post-treatment), deltamethrin provided 97% flea control and in residual toxicity it resulted in 68% control of the rodent fleas at 15-d post-treatment. The flea fauna consisted of Oropsylla montana (89.9%) and Hoplopsylls anomalus (10.1%). All rodents captured in this study were California ground squirrels, Spermophilus beecheyi. In mark-release-recapture trials, using the microchip identification implant method at the treatment site, the recapture rate of rodents was 29% from 2- to 58-d post-treatment, declining to 21% after 98 d. In the tail-clip method at the treatment site, the recapture rate of 40% at 15-d post-treatment rose to 87% and 73% at 56- and 58-d post-treatment, respectively. At the control site, the recapture rate of 100% at 15-d post-post-treatment dropped to 20% after 98 d. In another trial at Camp Cedar Crest in the Running Springs area, deltamethrin applied to rodent burrows resulted in 70% control of fleas infesting S. beecheyi. Based on the two trials, deltamethrin showed a good initial control of rodent fleas in enzootic or epizootic plague control. PMID:15707280

  8. The role of rodents in the ecology of Ixodes ricinus and associated pathogens in Central and Eastern Europe.

    PubMed

    Mihalca, Andrei D; Sándor, Attila D

    2013-01-01

    Rodents comprise more species than any other mammal order. Most rodents are considered keystone species in their ecological communities, hence the survival of many other species in the ecosystem depend on them. From medical point of view, this is particularly important for rodent-dependent pathogens. In the particular case of tick-borne diseases, rodents are important as hosts for vector ticks and as reservoir hosts (Lyme borreliosis, human granulocytic anaplasmosis, Crimean-Congo hemorrhagic fever, Tick-borne relapsing fevers, tick-borne rickettsioses, babesiosis). Community and population ecology of rodents was shown to be correlated with disease ecology in the case of many tick-borne diseases. In Eastern Europe, several adult hard-tick species use rodents as their principal hosts: Ixodes apronophorus, I. crenulatus, I. laguri, I. redikorzevi, I. trianguliceps. However, the majority of ticks feeding on rodents are immature stages of ticks which as adults are parasitic on larger mammals. Larvae and nymphs of Ixodes ricinus, the most abundant and medically important tick from Europe, are commonly found on rodents. This is particularly important, as many rodents are synanthropic and, together with other micromammals and birds are often the only available natural hosts for ticks in urban environments. This work reviews the correlated ecology of rodents and I. ricinus. PMID:24102049

  9. Rodent neurotoxicity bioassays for screening contaminated Great Lakes fish

    SciTech Connect

    Beattie, M.K.; Hoffman, R.; Gerstenberger, S.; Dellinger, J.A.

    1996-03-01

    Standard laboratory rat neurotoxicity protocols were used to study the consequences resulting from the consumption of walleye (Stizostedion vitreum), whitefish (Coregonus clupeaformis), and lake trout (Salvelinus namaycush) from Lake Superior (LS) and the consumption of carp (Cyprinus carpio) from Little Lake Butte des Morte (LLBM) near Oshkosh, Wisconsin, USA. Two 90-d subchronic studies are described, including a 45-d exposure to fish diets using male Sprague-Dawley hooded rats, and a 90-d exposure to fish diets using female rats of the same species. Behavioral alterations were tested using a battery of behavioral tests. In addition, pharmacologic challenges using apomorphine and D-amphetamine were administered to the rats to reveal latent neurotoxic effects. Cumulative fish consumption data were recorded daily, weight gain recorded weekly, and behavior data collected prior to exposure, and on days 7, 14, 55 {+-} 2, 85 {+-} 2. Motor activity data were collected on days 30 {+-} 2, 60 {+-} 2, and 90 {+-} 2 of the feeding protocols. Brain tissue from rodents fed these fish were subsequently analyzed for either mercury (Hg) or polychlorinated biphenyls (PCB). Mercury concentrations were increased in the brains of the walleye-fed rats, and PCB concentrations ranged from 0.5 nl/L to 10 nl/L in the brains of rats fed carp from LLBM, a Lake Michigan tributary. Adult male rats fed LLBM carp for 45 d exhibited the greatest behavior responses to the dopaminergic agonist apomorphine on the accelerating rotarod, although these differences were not significant. The 90-d exposure of LS walleye or Hg-spiked LS walleye resulted in behavior alterations on tactile startle response and second footsplay. D-Amphetamine challenge caused changes in tactile startle response, second footsplay, and accelerating rotarod performance after consuming walleye diets. Rats fed LLBM carp had altered behavioral responses to apomorphine on the accelerating rotarod.

  10. NASA Rodent Foodbar: Long Term Effects in Swiss Webster Mice

    NASA Technical Reports Server (NTRS)

    Santiago, D. L.; Yu, D. S.; Naficy, N. H.; Roghani, P. M.; Dalton, B. P.; Barrett, J. E.; Dalton, Bonnie (Technical Monitor)

    2001-01-01

    Swiss Webster male and female mice (150 of each) were fed NASA Rodent Foodbar for more than 110 days to test the diet's nutritional adequacy for use in future long-term studies aboard the International Space Station. Mice were grouped three to a cage (one cage = one sample) and cages were assigned to either Foodbar or Purina Chow #5001 (control) diet groups. Body weights, food intake, and water intake were obtained throughout the study. There were no significant differences in body weights between male Foodbar fed and Chow fed males (p=0.58), and at 15 weeks into the female mouse study there appear to be no significant body weight differences. Both male and female Foodbar fed groups consumed more food and less water than their Chow controls, both factors thought to be attributable to the high moisture content of the Foodbars (26% versus 10% for Chow). All differences in gross food and water consumption had p-values of less than 0.01. When food and water intake were adjusted for the moisture content in the food, both male and female Foodbar fed animals consumed less food, but still had a lower water intake rate than their controls. (p is less than 0.01). Preliminary analysis on blood samples from male and female halfway point dissections suggests differences in glucose and fat metabolism. In both male and female Foodbar fed animals, blood glucose values were significantly lower (p is less than 0.01) but there were no significant differences in cholesterol levels (p=0.51). In Foodbar fed females, triglycerides were significantly higher (p is less than 0.01). These data suggest that Foodbars allow for normal growth in Swiss Webster mice, but affect some blood chemistry parameters.

  11. Neonatal lead exposure impairs development of rodent barrel field cortex

    PubMed Central

    Wilson, Mary Ann; Johnston, Michael V.; Goldstein, Gary W.; Blue, Mary E.

    2000-01-01

    Childhood exposure to low-level lead can permanently reduce intelligence, but the neurobiologic mechanism for this effect is unknown. We examined the impact of lead exposure on the development of cortical columns, using the rodent barrel field as a model. In all areas of mammalian neocortex, cortical columns constitute a fundamental structural unit subserving information processing. Barrel field cortex contains columnar processing units with distinct clusters of layer IV neurons that receive sensory input from individual whiskers. In this study, rat pups were exposed to 0, 0.2, 1, 1.5, or 2 g/liter lead acetate in their dam's drinking water from birth through postnatal day 10. This treatment, which coincides with the development of segregated columns in the barrel field, produced blood lead concentrations from 1 to 31 ?g/dl. On postnatal day 10, the area of the barrel field and of individual barrels was measured. A dose-related reduction in barrel field area was observed (Pearson correlation = ?0.740; P < 0.001); mean barrel field area in the highest exposure group was decreased 12% versus controls. Individual barrels in the physiologically more active caudoventral group were affected preferentially. Total cortical area measured in the same sections was not altered significantly by lead exposure. These data support the hypothesis that lead exposure may impair the development of columnar processing units in immature neocortex. We demonstrate that low levels of blood lead, in the range seen in many impoverished inner-city children, cause structural alterations in a neocortical somatosensory map. PMID:10805810

  12. Lung Function Measurements in Rodents in Safety Pharmacology Studies

    PubMed Central

    Hoymann, Heinz Gerd

    2012-01-01

    The ICH guideline S7A requires safety pharmacology tests including measurements of pulmonary function. In the first step as part of the core battery lung function tests in conscious animals are requested. If potential adverse effects raise concern for human safety, these should be explored in a second step as a follow-up study. For these two stages of safety pharmacology testing, both non-invasive and invasive techniques are needed which should be as precise and reliable as possible. A short overview of typical in vivo measurement techniques is given, their advantages and disadvantages are discussed and out of these the non-invasive head-out body plethysmography and the invasive but repeatable body plethysmography in orotracheally intubated rodents are presented in detail. For validation purposes the changes in the respective parameters such as tidal midexpiratory flow (EF50) or lung resistance have been recorded in the same animals in typical bronchoconstriction models and compared. In addition, the technique of head-out body plethysmography has been shown to be useful to measure lung function in juvenile rats starting from day two of age. This allows safety pharmacology testing and toxicological studies in juvenile animals as a model for the young developing organism as requested by the regulatory authorities (e.g., EMEA Guideline 1/2008). It is concluded that both invasive and non-invasive pulmonary function tests are capable of detecting effects and alterations on the respiratory system with different selectivity and area of operation. The use of both techniques in a large number of studies in mice and rats in the last years have demonstrated that they provide useful and reliable information on pulmonary mechanics in safety pharmacology and toxicology testing, in investigations of respiratory disorders, and in pharmacological efficacy studies. PMID:22973226

  13. Assays of homeopathic remedies in rodent behavioural and psychopathological models.

    PubMed

    Bellavite, Paolo; Magnani, Paolo; Marzotto, Marta; Conforti, Anita

    2009-10-01

    The first part of this paper reviews the effects of homeopathic remedies on several models of anxiety-like behaviours developed and described in rodents. The existing literature in this field comprises some fifteen exploratory studies, often published in non-indexed and non-peer-reviewed journals. Only a few results have been confirmed by multiple laboratories, and concern Ignatia, Gelsemium, Chamomilla (in homeopathic dilutions/potencies). Nevertheless, there are some interesting results pointing to the possible efficacy of other remedies, and confirming a statistically significant effect of high dilutions of neurotrophic molecules and antibodies. In the second part of this paper we report some recent results obtained in our laboratory, testing Aconitum, Nux vomica, Belladonna, Argentum nitricum, Tabacum (all 5CH potency) and Gelsemium (5, 7, 9 and 30CH potencies) on mice using ethological models of behaviour. The test was performed using coded drugs and controls in double blind (operations and calculations). After an initial screening that showed all the tested remedies (except for Belladonna) to have some effects on the behavioural parameters (light-dark test and open-field test), but with high experimental variability, we focused our study on Gelsemium, and carried out two complete series of experiments. The results showed that Gelsemium had several effects on the exploratory behaviour of mice, which in some models were highly statistically significant (p < 0.001), in all the dilutions/dynamizations used, but with complex differences according to the experimental conditions and test performed. Finally, some methodological issues of animal research in this field of homeopathy are discussed. The "Gelsemium model" - encompassing experimental studies in vitro and in vivo from different laboratories and with different methods, including significant effects of its major active principle gelsemine - may play a pivotal rule for investigations on other homeopathic remedies. PMID:19945676

  14. Expensive Brains: Brainy Rodents have Higher Metabolic Rate

    PubMed Central

    Sobrero, Ral; May-Collado, Laura J.; Agnarsson, Ingi; Hernndez, Cristin E.

    2011-01-01

    Brains are the centers of the nervous system of animals, controlling the organ systems of the body and coordinating responses to changes in the ecological and social environment. The evolution of traits that correlate with cognitive ability, such as relative brain size is thus of broad interest. Brain mass relative to body mass (BM) varies among mammals, and diverse factors have been proposed to explain this variation. A recent study provided evidence that energetics play an important role in brain evolution (Isler and van Schaik, 2006). Using composite phylogenies and data drawn from multiple sources, these authors showed that basal metabolic rate (BMR) correlates with brain mass across mammals. However, no such relationship was found within rodents. Here we re-examined the relationship between BMR and brain mass within Rodentia using a novel species-level phylogeny. Our results are sensitive to parameter evaluation; in particular how species mass is estimated. We detect no pattern when applying an approach used by previous studies, where each species BM is represented by two different numbers, one being the individual that happened to be used for BMR estimates of that species. However, this approach may compromise the analysis. When using a single value of BM for each species, whether representing a single individual, or available species mean, our findings provide evidence that brain mass (independent of BM) and BMR are correlated. These findings are thus consistent with the hypothesis that large brains evolve when the payoff for increased brain mass is greater than the energetic cost they incur. PMID:21811456

  15. Reprogramming the Cell Cycle for Endoreduplication in Rodent Trophoblast Cells

    PubMed Central

    MacAuley, Alasdair; Cross, James C.; Werb, Zena

    1998-01-01

    Differentiation of trophoblast giant cells in the rodent placenta is accompanied by exit from the mitotic cell cycle and onset of endoreduplication. Commitment to giant cell differentiation is under developmental control, involving down-regulation of Id1 and Id2, concomitant with up-regulation of the basic helix-loop-helix factor Hxt and acquisition of increased adhesiveness. Endoreduplication disrupts the alternation of DNA synthesis and mitosis that maintains euploid DNA content during proliferation. To determine how the mammalian endocycle is regulated, we examined the expression of the cyclins and cyclin-dependent kinases during the transition from replication to endoreduplication in the Rcho-1 rat choriocarcinoma cell line. We cultured these cells under conditions that gave relatively synchronous endoreduplication. This allowed us to study the events that occur during the transition from the mitotic cycle to the first endocycle. With giant cell differentiation, the cells switched cyclin D isoform expression from D3 to D1 and altered several checkpoint functions, acquiring a relative insensitivity to DNA-damaging agents and a coincident serum independence. The initiation of S phase during endocycles appeared to involve cycles of synthesis of cyclins E and A, and termination of S was associated with abrupt loss of cyclin A and E. Both cyclins were absent from gap phase cells, suggesting that their degradation may be necessary to allow reinitiation of the endocycle. The arrest of the mitotic cycle at the onset of endoreduplication was associated with a failure to assemble cyclin B/p34cdk1 complexes during the first endocycle. In subsequent endocycles, cyclin B expression was suppressed. Together these data suggest several points at which cell cycle regulation could be targeted to shift cells from a mitotic to an endoreduplicative cycle. PMID:9529378

  16. Lung imaging in rodents using dual energy micro-CT

    NASA Astrophysics Data System (ADS)

    Badea, C. T.; Guo, X.; Clark, D.; Johnston, S. M.; Marshall, C.; Piantadosi, C.

    2012-03-01

    Dual energy CT imaging is expected to play a major role in the diagnostic arena as it provides material decomposition on an elemental basis. The purpose of this work is to investigate the use of dual energy micro-CT for the estimation of vascular, tissue, and air fractions in rodent lungs using a post-reconstruction three-material decomposition method. We have tested our method using both simulations and experimental work. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact lungs were carefully removed from the thorax, were injected with an iodine-based contrast agent and inflated with air at different volume levels. Finally, we performed in vivo imaging studies in (n=5) C57BL/6 mice using fast prospective respiratory gating in endinspiration and end-expiration for three different levels of positive end-expiratory pressure (PEEP). Prior to imaging, mice were injected with a liposomal blood pool contrast agent. The mean accuracy values were for Air (95.5%), Blood (96%), and Tissue (92.4%). The absolute accuracy in determining all fraction materials was 94.6%. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end-expiration, but no significant changes in end-inspiration. Our method has applicability in preclinical pulmonary studies where various physiological changes can occur as a result of genetic changes, lung disease, or drug effects.

  17. Dual-energy micro-CT of the rodent lung.

    PubMed

    Badea, C T; Guo, X; Clark, D; Johnston, S M; Marshall, C D; Piantadosi, C A

    2012-05-15

    The purpose of this work is to investigate the use of dual-energy micro-computed tomography (CT) for the estimation of vascular, tissue, and air fractions in rodent lungs using a postreconstruction three material decomposition method. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact rat lungs were carefully removed from the thorax, injected with an iodine-based contrast agent, and then inflated with different volumes of air (n = 2). Finally, we performed in vivo imaging studies in C57BL/6 mice (n = 5) using fast prospective respiratory gating in end inspiration and end expiration for three different levels of positive end expiratory pressure (PEEP). Before imaging, mice were injected with a liposomal blood pool contrast agent. The three-dimensional air, tissue, and blood fraction maps were computed and analyzed. The results indicate that separation and volume estimation of the three material components of the lungs are possible. The mean accuracy values for air, blood, and tissue were 93, 93, and 90%, respectively. The absolute accuracy in determining all fraction materials was 91.6%. The coefficient of variation was small (2.5%) indicating good repeatability. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end expiration but no significant changes at end inspiration. Our method has applicability in preclinical pulmonary studies where changes in lung structure and gas volume as a result of lung injury, environmental exposures, or drug bioactivity would have important physiological implications. PMID:22427526

  18. Stress induced obesity: lessons from rodent models of stress

    PubMed Central

    Patterson, Zachary R.; Abizaid, Alfonso

    2013-01-01

    Stress was once defined as the non-specific result of the body to any demand or challenge to homeostasis. A more current view of stress is the behavioral and physiological responses generated in the face of, or in anticipation of, a perceived threat. The stress response involves activation of the sympathetic nervous system and recruitment of the hypothalamic-pituitary-adrenal (HPA) axis. When an organism encounters a stressor (social, physical, etc.), these endogenous stress systems are stimulated in order to generate a fight-or-flight response, and manage the stressful situation. As such, an organism is forced to liberate energy resources in attempt to meet the energetic demands posed by the stressor. A change in the energy homeostatic balance is thus required to exploit an appropriate resource and deliver useable energy to the target muscles and tissues involved in the stress response. Acutely, this change in energy homeostasis and the liberation of energy is considered advantageous, as it is required for the survival of the organism. However, when an organism is subjected to a prolonged stressor, as is the case during chronic stress, a continuous irregularity in energy homeostasis is considered detrimental and may lead to the development of metabolic disturbances such as cardiovascular disease, type II diabetes mellitus and obesity. This concept has been studied extensively using animal models, and the neurobiological underpinnings of stress induced metabolic disorders are beginning to surface. However, different animal models of stress continue to produce divergent metabolic phenotypes wherein some animals become anorexic and lose body mass while others increase food intake and body mass and become vulnerable to the development of metabolic disturbances. It remains unclear exactly what factors associated with stress models can be used to predict the metabolic outcome of the organism. This review will explore a variety of rodent stress models and discuss the elements that influence the metabolic outcome in order to further extend our understanding of stress-induced obesity. PMID:23898237

  19. Memory deficits associated with khat (Catha edulis) use in rodents.

    PubMed

    Kimani, S T; Patel, N B; Kioy, P G

    2016-02-01

    Khat products and chewing practices are common in East Africa, Middle East for centuries with concomitant socio-economic and public health repercussions. We assessed memory deficits associated with khat use in rodents. Young male CBA mice, 5-7weeks old (n?=?20), weighing 25-35g were used. Mice were treated with either 40, 120 or 360mg/kg body weight (bw) methanolic khat extract, or 0.5ml saline for 10days. Spatial acquisition, reversal and reference memory were assessed using modified Morris Water maze (MMWM). Mice treated with 40mg/kg khat extract had longer (t4?=?4.12 p?=?0.015) and t4?=?2.28 p?=?0.065) escape latency on first and second day during reversal relative to the baseline. Under 120mg/kg khat dose, the escape latency was shorter (t4?=?-2.49 p?=?0.05) vs (t3?=?-2.5 p?=?0.05) on third and fourth day. Further, treatment with 360mg/kg khat extract resulted in significantly longer time (49.13, 33.5, 40.2 and 35.75) vs. (23.5s), compared to baseline. Mice treated with khat or control preferred the target quadrant post acquisition while differential pattern was seen during reversal phase. Mice treated with 40 or 120mg/kg khat showed significant preference for target quadrant. Substantial time (19.9) was spent in the old target compared to the new (16.9s) by animals treated with highest dose however, the difference was not significant. There is a biological plausibility that chronic khat use may induce memory deficits and impair cognitive flexibility. The differential patterns of memory deficits may reflect the differences in dose effect as well as time dependent impairment. PMID:26423676

  20. High abundant protein removal from rodent blood for biomarker discovery

    PubMed Central

    Haudenschild, Dominik R.; Eldridge, Angela; Lein, Pamela J.; Chromy, Brett A.

    2014-01-01

    In order to realize the goal of stratified and/or personalized medicine in the clinic, significant advances in the field of biomarker discovery are necessary. Adding to the abundance of nucleic acid biomarkers being characterized, additional protein biomarkers will be needed to satisfy diverse clinical needs. An appropriate source for finding these biomarkers is within blood, as it contains tissue leakage factors as well as additional proteins that reside in blood that can be linked to the presence of disease. Unfortunately, high abundant proteins and complexity of the blood proteome present significant challenges for the discovery of protein biomarkers from blood. Animal models often enable the discovery of biomarkers that can later be translated to humans. Therefore, determining appropriate sample preparation of proteomic samples in rodent models is an important research goal. Here, we examined both mouse and rat blood samples (including both serum and plasma), for appropriate high abundant protein removal techniques for subsequent gel-based proteomic experiments. We assessed four methods of albumin removal: antibody-based affinity chromatography (MARS), Cibacron® Blue-based affinity depletion (SwellGel® Blue Albumin Removal Kit), protein-based affinity depletion (ProteaPrep Albumin Depletion Kit) and TCA/acetone precipitation. Albumin removal was quantified for each method and SDS-PAGE and 2-DE gels were used to quantify the number of protein spots obtained following albumin removal. Our results suggest that while all four approaches can effectively remove high abundant proteins, antibody-based affinity chromatography is superior to the other three methods. PMID:25445603