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Jean-françois Pflieger - One of the best experts on this subject based on the ideXlab platform.
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Cephalic sensory influence on forelimb movement in newborn Opossums, Monodelphis domestica.
Neuroscience, 2012Co-Authors: T. Adadja, Thérèse Cabana, Jean-françois PfliegerAbstract:Abstract Like other marsupials, the opossum Monodelphis domestica is born very immature and crawls, unaided by the mother, from the urogenital opening to a nipple where it attaches and pursues its development. If the alternate, rhythmic movements of the forelimbs which allow this locomotion are generated by the developing spinal motor networks, sensory information is nonetheless needed to guide the newborn to a nipple. Behavioral, anatomical and physiological studies suggest that the auditory and the visual systems are insufficiently developed in newborn Opossums to influence spinal motor centers, while the vestibular, trigeminal, and olfactory systems are likelier candidates. The trigeminal, vestibular and olfactory regions of the brain were electrically stimulated to test their relative effectiveness at eliciting forelimb movement in newborn Opossums, using in vitro preparations of brain-spinal cord with the limbs attached. The minimal stimulation of the cervical spinal cord needed to induce forelimb movement was considered as threshold (T). Stimulations of the trigeminal ganglion (5G) at ∼2 T and of the vestibular complex at ∼20 T could induce the same movement, and were not statistically different, in contrast to the ∼600 T necessary for the olfactory bulb (OB). Neurofilament-200 immunohistochemistry and retrograde tracing with Texas-Red conjugated Dextran Amines were used to study trigeminal innervation of the facial skin and pathways by which trigeminal inputs may be relayed to the spinal cord. Numerous nerve fibers were observed in the snout dermis, especially in the maxillary region, but also elsewhere in the head skin. Some 5G cells project to the upper spinal cord, but more project to the caudal medulla where they could contact secondary trigeminal neurons or reticular cells projecting to the spinal cord. These results support a significant influence of the trigeminal and the vestibular systems, but not of olfaction, on forelimb movement of neonatal Opossums.
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Developmental expression of spontaneous activity in the spinal cord of postnatal Opossums, Monodelphis domestica: an anatomical study.
Brain Research, 2009Co-Authors: Annie Lavallée, Jean-françois PfliegerAbstract:Abstract Using Sulforhodamine-101 (SR101) labeling and calcium imaging on in vitro preparations, we investigated the development of spontaneous activity in the spinal enlargements of a marsupial born more immature than eutherian mammals, the opossum Monodelphis domestica . Following the retrograde transport of Calcium Green dye from the limb nerves, we observed the occurrence of spontaneous calcium waves activating the motor columns of the cervical enlargement of Opossums aged from P3 to P15 (day of birth: P0) and of the lumbar enlargement from at least P6 to P12. In other preparations, SR101 was added to the bath to identify the active cells. In P1 Opossums, only a few SR101-labeled cells were observed in the cervical enlargement and none in the lumbar enlargement. At P5, their number increased cervically and they appeared in the lumbar enlargement. Motoneurons were the major cell type labeled by SR101 but dye leakage made their quantification inaccurate. SR101-labeled cells also occurred elsewhere in the ventral and dorsal grey. Their number increased until P12–14 in both enlargements and then decreased to disappear by P21, the last age examined. Thus in contrast to eutherian mammals, in which spontaneous activity is mostly prenatal, spontaneous activity occurs predominantly postnatally in Opossums. It increases at the time when connections from the brain begin to impinge on spinal neurons and when the limbs, especially the hindlimbs, start moving and then decreases as the systems mature.
J P Dubey - One of the best experts on this subject based on the ideXlab platform.
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besnoitia oryctofelisi n sp protozoa apicomplexa from domestic rabbits
Parasitology, 2003Co-Authors: J P Dubey, C Sreekumar, David S Lindsay, D E Hill, Benjamin M Rosenthal, L Venturini, M C Venturini, Ellis C GreinerAbstract:A species of Besnoitia from naturally infected rabbits from Argentina was propagated experimentally in mice, gerbils, rabbits, cats, and cell cultures. Cats fed tissue cysts from rabbits shed oocysts with a prepatent period of nine to 13 days. Sporulated oocysts were infective to gerbils, rabbits, outbred Swiss Webster and interferon gamma gene knockout mice. Bradyzoites were infective orally to gerbils and cats. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells. Schizonts were seen in the lamina propria of the small intestine of cats fed tissue cysts; the largest ones measured 52×45 μm. Schizonts were also present in mesenteric lymph nodes, livers, and other extra-intestinal organs of cats fed tissue cysts. Oocysts were 10–14×10–13 μm in size. This rabbit-derived species of Besnoitia resembled B. darlingi of the North American opossum, Didelphis virginiana with an opossum-cat cycle, but it was not transmissible to D. virginiana , and B. darlingi of Opossums was not transmissible to rabbits. Based on biological, serological, antigenic, and molecular differences between the rabbit and the opossum Besnoitia , a new name, B. oryctofelisi is proposed for the parasite from domestic rabbits from Argentina.
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risk factors associated with the presence of sarcocystis neurona sporocysts in Opossums didelphis virginiana
Veterinary Parasitology, 2001Co-Authors: L G Rickard, S S Black, G Hurst, Ann M Rashmirraven, J P DubeyAbstract:Sarcocystis neurona is the most important cause of equine protozoal myeloencephalitis (EPM) in horse in the Americas. The only known definitive host for this parasite in the United States is the opossum (Didelphis virginiana); however, despite the importance of the disease, the epidemiology of the parasite in the definitive host is poorly understood. To begin addressing these data gaps, potential risk factors were evaluated for their association with the presence of sporocysts of S. neurona in Opossums live-trapped in March 1999 and November 1999 to May 2000. Sporocysts of S. neurona were found in 19 of the 72 animals examined. Potential risk factors evaluated were locality, trap date, age, gender, the presence of young in the pouch of females, and body condition score. Variables that were associated with the presence of S. neurona sporocysts were used in logistic regression analysis. Of the factors examined, season and body condition score were associated with increased odds of an animal harboring sporocysts.
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sarcocystis neurona infections in raccoons procyon lotor evidence for natural infection with sarcocysts transmission of infection to Opossums didelphis virginiana and experimental induction of neurologic disease in raccoons
Veterinary Parasitology, 2001Co-Authors: J P Dubey, David S Lindsay, Benjamin M Rosenthal, W J A Saville, J F Stanek, Michael Oglesbee, Alexa C Rosypal, C J Njoku, Roger W Stich, O C KwokAbstract:Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease of horses in the Americas and Sarcocystis neurona is the most common etiologic agent. The distribution of S. neurona infections follows the geographical distributions of its definitive hosts, Opossums (Didelphis virginiana, Didelphis albiventris). Recently, cats and skunks were reported as experimental and armadillos as natural intermediate hosts of S. neurona. In the present report, raccoons (Procyon lotor) were identified as a natural intermediate host of S. neurona. Two laboratory-raised Opossums were found to shed S. neurona-like sporocysts after ingesting tongues of naturally-infected raccoons. Interferon-gamma gene knockout (KO) mice fed raccoon-opossum-derived sporocysts developed neurologic signs. S. neurona was identified immunohistochemically in tissues of KO mice fed sporocysts and the parasite was isolated in cell cultures inoculated with infected KO mouse tissues. The DNA obtained from the tongue of a naturally-infected raccoon, brains of KO mice that had neurological signs, and from the organisms recovered in cell cultures inoculated with brains of neurologic KO mice, corresponded to that of S. neurona. Two raccoons fed mature S. neurona sarcocysts did not shed sporocysts in their feces, indicating raccoons are not likely to be its definitive host. Two raccoons fed sporocysts from opossum feces developed clinical illness and S. neurona-associated encephalomyelitis was found in raccoons killed 14 and 22 days after feeding sporocysts; schizonts and merozoites were seen in encephalitic lesions.
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Prevalence of Sarcocystis neurona sporocysts in Opossums (Didelphis virginiana) from rural Mississippi.
Veterinary parasitology, 2001Co-Authors: J P Dubey, S S Black, L G Rickard, B M Rosenthal, D S Lindsay, S K Shen, O C Kwok, G Hurst, A Rashmir-ravenAbstract:Sarcocystis species sporocysts were found in intestinal scrapings from 24 of 72 Opossums (Didelphis virginiana) from rural Mississippi. The number of sporocysts in each opossum varied from a few ( < 100000) to 187 million. Sporocysts from 24 Opossums were bioassayed for Sarcocystis neurona infections by feeding to gamma-interferon knockout (KO) mice. S. neurona was detected in the brains of KO mice fed sporocysts from 19 Opossums by immunohistochemical staining with anti-S. neurona specific polyclonal rabbit serum, and by in vitro culture from the brains of KO mice fed sporocysts. The isolates of S. neurona from Opossums were designated SN16-OP to SN34-OP. Merozoites from 17 of 19 isolates tested at the 25/396 locus were identical to previously described S. neurona isolates from horses. The high prevalence of S. neurona sparocysts in D. virginiana suggests that this opossum constitutes an ample reservoir of infection in the southern United States.
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prevalence of sarcocystis neurona sporocysts in Opossums didelphis virginiana from rural mississippi
Veterinary Parasitology, 2001Co-Authors: J P Dubey, David S Lindsay, Benjamin M Rosenthal, S S Black, L G Rickard, S K Shen, O C Kwok, G Hurst, Ann M RashmirravenAbstract:Abstract Sarcocystis species sporocysts were found in intestinal scrapings from 24 of 72 Opossums ( Didelphis virginiana ) from rural Mississippi. The number of sporocysts in each opossum varied from a few ( Sarcocystis neurona infections by feeding to gamma-interferon knockout (KO) mice. S. neurona was detected in the brains of KO mice fed sporocysts from 19 Opossums by immunohistochemical staining with anti -S. neurona specific polyclonal rabbit serum, and by in vitro culture from the brains of KO mice fed sporocysts. The isolates of S. neurona from Opossums were designated SN16-OP to SN34-OP. Merozoites from 17 of 19 isolates tested at the 25/396 locus were identical to previously described S. neurona isolates from horses. The high prevalence of S. neurona sparocysts in D. virginiana suggests that this opossum constitutes an ample reservoir of infection in the southern United States.
Leah Krubitzer - One of the best experts on this subject based on the ideXlab platform.
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performance and behavioral flexibility on a complex motor task depend on available sensory inputs in early blind and sighted short tailed Opossums
bioRxiv, 2020Co-Authors: Mackenzie Englund, Samaan Faridjoo, Chris Iyer, Leah KrubitzerAbstract:The early loss of vision results in a reorganized visual cortex that processes tactile and auditory inputs. Recent studies in the short-tailed opossum (Monodelphis domestica) found that the connections and response properties of neurons in somatosensory cortex of early blind animals are also altered. While research in humans and other mammals shows that early vision loss leads to heightened abilities on discrimination tasks involving the spared senses, if and how this superior discrimination leads to adaptive sensorimotor behavior has yet to be determined. Moreover, little is known about the extent to which blind animals rely on the spared senses. Here, we tested early blind Opossums on a sensorimotor task involving somatosensation and found that they had increased limb placement accuracy. However, increased reliance on tactile inputs in early blind animals resulted in greater deficits in limb placement and behavioral flexibility when the whiskers were trimmed.
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Photic preference of the short-tailed opossum (Monodelphis domestica)
Neuroscience, 2014Co-Authors: Adele M. H. Seelke, James C. Dooley, Leah KrubitzerAbstract:The gray short-tailed opossum (Monodelphis domestica) is a nocturnal South American marsupial that has been gaining popularity as a laboratory animal. However, compared to traditional laboratory animals like rats, very little is known about its behavior, either in the wild or in a laboratory setting. Here we investigated the photic preference of the short-tailed opossum. Opossums were placed in a circular testing arena and allowed to move freely between dark (0 lux) and light (∼1.4, 40, or 400 lux) sides of the arena. In each of these conditions Opossums spent significantly more time in the dark than in the illuminated side and a greater proportion of time in the dark than would be expected by chance. In the high-contrast (∼400 lux) illumination condition, the mean bout length (i.e., duration of one trip on the light or dark side) was significantly longer on the dark side than on the light side. When we examined the number of bouts greater than 30 and 60s in duration, we found a significant difference between the light and dark sides in all light contrast conditions. These data indicate that the short-tailed opossum prefers the dark to the light, and can also detect very slight differences in light intensity. We conclude that although rats and Opossums share many similar characteristics, including ecological niche, their divergent evolutionary heritage results in vastly different behavioral capabilities. Only by observing the behavioral capabilities and preferences of Opossums will we be able to manipulate the experimental environment to best elicit and elucidate their behavior and alterations in behavior that can arise from experimental manipulations.
David S Lindsay - One of the best experts on this subject based on the ideXlab platform.
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identification of Opossums didelphis aurita wied neuweid 1826 as a definitive host of sarcocystis falcatula like sporocysts
Parasitology Research, 2018Co-Authors: Samira Salim Mello Gallo, David S Lindsay, Nicole Brand Ederli, Filipe P Matteoli, Thiago M Venancio, Francisco Carlos Rodrigues De OliveiraAbstract:This study was conducted to identify the Sarcocystis species that infect the opossum Didelphis aurita in order to determine which sporocysts they are excreating in to the environment and help determine the role of D. aurita in the epidemiology of Sarcocystis. Sporocysts were obtained from intestinal tracts of 8 of 13 D. aurita trapped in Rio de Janeiro state, Brazil, and were orally inoculated into Melopsittacus undulatus and Balb/c nude Mus musculus. Portions of organs and muscles were processed for histology, immunohistochemistry, transmission electron microscopy (TEM), and PCR using primers JNB 33/54, and ITS. Amplification products were subjected to RFLP using DraI and HinfI. Some birds were euthanized 6, 7, 13, 16, and 24 days after inoculation (DAI). All other birds and all mice were euthanized 60 DAI. Schizonts were observed in the lungs using histology and immunostaining in birds examined prior to 60 DAI. Sarcocysts with a ~ 1.5-μm-thick wall were found in the breast, thigh, and tongue of some birds. Sarcocystis asexual stages were isolated in cell cultures inoculated with sporozoites. Parasite DNA isolated from bird tissues and cell cultures demonstrated that S. falcatula-like parasites were present in all samples derived from positive Opossums. Asexual stages molecularly characterized as S. lindsayi-like were isolated in cell culture from one opossum with an apparent multiple infection. This study demonstrated that D. aurita is a definitive host for S. falcatula-like parasites and indicates that S. lindsayi-like parasites can be found in coinfections of this opossum species.
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A review of Sarcocystis spp. shed by Opossums (Didelphis spp.) in Brazil
Brazilian Journal of Veterinary Research and Animal Science, 2016Co-Authors: Samantha Yuri Oshiro Branco Valadas, Rodrigo Martins Soares, David S LindsayAbstract:South American Opossums are the definitive hosts of Sarcocystis neurona, Sarcocystis falcatula, Sarcocystis speeri and Sarcocystis lindsayi. The sporocysts of these species of Sarcocystis are morphologically similar and methods like infectivity and pathogenicity for intermediate hosts (immunodeficient mice and psittacine birds) and molecular tools are used for identification. Opossums are synanthropic wild animals, and widely distributed in Brazilian territory. Previous studies have shown high environmental contamination with S. neurona sporocysts in several Brazilian regions. This paper reviews information on Sarcocystis spp. shed by various opossum species and its occurrence in Brazil.
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besnoitia oryctofelisi n sp protozoa apicomplexa from domestic rabbits
Parasitology, 2003Co-Authors: J P Dubey, C Sreekumar, David S Lindsay, D E Hill, Benjamin M Rosenthal, L Venturini, M C Venturini, Ellis C GreinerAbstract:A species of Besnoitia from naturally infected rabbits from Argentina was propagated experimentally in mice, gerbils, rabbits, cats, and cell cultures. Cats fed tissue cysts from rabbits shed oocysts with a prepatent period of nine to 13 days. Sporulated oocysts were infective to gerbils, rabbits, outbred Swiss Webster and interferon gamma gene knockout mice. Bradyzoites were infective orally to gerbils and cats. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells. Schizonts were seen in the lamina propria of the small intestine of cats fed tissue cysts; the largest ones measured 52×45 μm. Schizonts were also present in mesenteric lymph nodes, livers, and other extra-intestinal organs of cats fed tissue cysts. Oocysts were 10–14×10–13 μm in size. This rabbit-derived species of Besnoitia resembled B. darlingi of the North American opossum, Didelphis virginiana with an opossum-cat cycle, but it was not transmissible to D. virginiana , and B. darlingi of Opossums was not transmissible to rabbits. Based on biological, serological, antigenic, and molecular differences between the rabbit and the opossum Besnoitia , a new name, B. oryctofelisi is proposed for the parasite from domestic rabbits from Argentina.
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sarcocystis neurona infections in raccoons procyon lotor evidence for natural infection with sarcocysts transmission of infection to Opossums didelphis virginiana and experimental induction of neurologic disease in raccoons
Veterinary Parasitology, 2001Co-Authors: J P Dubey, David S Lindsay, Benjamin M Rosenthal, W J A Saville, J F Stanek, Michael Oglesbee, Alexa C Rosypal, C J Njoku, Roger W Stich, O C KwokAbstract:Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease of horses in the Americas and Sarcocystis neurona is the most common etiologic agent. The distribution of S. neurona infections follows the geographical distributions of its definitive hosts, Opossums (Didelphis virginiana, Didelphis albiventris). Recently, cats and skunks were reported as experimental and armadillos as natural intermediate hosts of S. neurona. In the present report, raccoons (Procyon lotor) were identified as a natural intermediate host of S. neurona. Two laboratory-raised Opossums were found to shed S. neurona-like sporocysts after ingesting tongues of naturally-infected raccoons. Interferon-gamma gene knockout (KO) mice fed raccoon-opossum-derived sporocysts developed neurologic signs. S. neurona was identified immunohistochemically in tissues of KO mice fed sporocysts and the parasite was isolated in cell cultures inoculated with infected KO mouse tissues. The DNA obtained from the tongue of a naturally-infected raccoon, brains of KO mice that had neurological signs, and from the organisms recovered in cell cultures inoculated with brains of neurologic KO mice, corresponded to that of S. neurona. Two raccoons fed mature S. neurona sarcocysts did not shed sporocysts in their feces, indicating raccoons are not likely to be its definitive host. Two raccoons fed sporocysts from opossum feces developed clinical illness and S. neurona-associated encephalomyelitis was found in raccoons killed 14 and 22 days after feeding sporocysts; schizonts and merozoites were seen in encephalitic lesions.
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prevalence of sarcocystis neurona sporocysts in Opossums didelphis virginiana from rural mississippi
Veterinary Parasitology, 2001Co-Authors: J P Dubey, David S Lindsay, Benjamin M Rosenthal, S S Black, L G Rickard, S K Shen, O C Kwok, G Hurst, Ann M RashmirravenAbstract:Abstract Sarcocystis species sporocysts were found in intestinal scrapings from 24 of 72 Opossums ( Didelphis virginiana ) from rural Mississippi. The number of sporocysts in each opossum varied from a few ( Sarcocystis neurona infections by feeding to gamma-interferon knockout (KO) mice. S. neurona was detected in the brains of KO mice fed sporocysts from 19 Opossums by immunohistochemical staining with anti -S. neurona specific polyclonal rabbit serum, and by in vitro culture from the brains of KO mice fed sporocysts. The isolates of S. neurona from Opossums were designated SN16-OP to SN34-OP. Merozoites from 17 of 19 isolates tested at the 25/396 locus were identical to previously described S. neurona isolates from horses. The high prevalence of S. neurona sparocysts in D. virginiana suggests that this opossum constitutes an ample reservoir of infection in the southern United States.
Linda S. Mansfield - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic relationships of Sarcocystis neurona of horses and Opossums to other cyst-forming coccidia deduced from SSU rRNA gene sequences
Parasitology Research, 2005Co-Authors: Hany M. Elsheikha, David W. Lacher, Linda S. MansfieldAbstract:Phylogenetic analyses based on sequences of the nuclear-encoded small subunit rRNA (ssurRNA) gene were performed to examine the origin, phylogeny, and biogeographic relationships of Sarcocystis neurona isolates from Opossums and horses from the State of Michigan, USA, in relation to other cyst-forming coccidia. A total of 31 taxa representing all recognized subfamilies and genera of Sarcocystidae were included in the analyses with clonal isolates of two opossum and two horse S. neurona . Phylogenies obtained by the four tree-building methods were consistent with the classical taxonomy based on morphological criteria. The “isosporid” coccidia Neospora , Toxoplasma , Besnoitia , Isospora lacking stieda bodies, and Hyaloklossia formed a sister group to the Sarcocystis spp. Sarcocystis species were divided into three main lineages; S. neurona isolates were located in the second lineage and clustered with S. mucosa , S. dispersa , S. lacertae , S. rodentifelis , S. muris , and Frenkelia spp. Alignment of S. neurona SSU rRNA gene sequences of Michigan opossum isolates (MIOP5, MIOP20) and a S. neurona Michigan horse isolate (MIH8) showed 100% identity. These Michigan isolates differed in 2/1085 bp (0.2%) from a Kentucky S. neurona horse isolate (SN5). Additionally, S. neurona isolates from horses and Opossums were identical based on the ultrastructural features and PCR-RFLP analyses thus forming a phylogenetically indistinct group in these regions. These findings revealed the concordance between the morphological and molecular data and confirmed that S. neurona from Opossums and horses originated from the same phylogenetic origin.
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prevalence of sarcocystis species sporocysts in northern virginia Opossums didelphis virginiana
Parasitology Research, 2004Co-Authors: Hany M. Elsheikha, Alice J Murphy, Linda S. MansfieldAbstract:A total of 206 Virginia Opossums (Didelphis virginiana) collected from the mid-Michigan region, United States, during a period extending from 1996 to 2002 were sampled for the presence of Sarcocystis spp sporocysts. All isolates were phenotypically identified as Sarcocystis spp and genotyped to the species level by PCR-based techniques. The overall prevalence of Sarcocystis spp in Opossums was 18% (37/206). The prevalence of Sarcocystis spp differed significantly with age (P<0.001) and adult Opossums were more commonly infected (14.6%; 30/206) than juveniles (3.4%; 7/206). No significant difference in the prevalence of Sarcocystis spp infection was observed between male and female (P<0.15). The highest prevalence was recorded during summer (9.2%; 19/206). PCR-RFLP analyses demonstrated the majority of Sarcocystis isolates to be S. neurona, with some animals co-infected with sporocysts of S. falcatula. Out of the 37 Sarcocystis-infected Opossums, 23 (62%) had sporocysts of S. neurona only, four (11%) had sporocysts of S. falcatula only, and eight (22%) had a mixture of S. neurona and S. falcatula sporocysts. These findings indicate that mixed Sarcocystis infections in Opossums are common. The propensity for Sarcocystis spp to co-exist in the opossum gut enhances dissemination and environmental contamination with these coccidia. Additionally, this increases the chance for sexual recombination between Sarcocystis spp, given the proclivity of these species to reproduce sexually at high numbers in the intestinal cells of their definitive host.
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Sarcocystis inghami n. sp. (Sporozoa: Sarcocystidae) from the skeletal muscles of the Virginia opossum Didelphis virginiana in Michigan
Systematic Parasitology, 2003Co-Authors: Hany M. Elsheikha, Linda S. Mansfield, Scott D. Fitzgerald, A. Mahdi SaeedAbstract:This report describes the newly identified Sarcocystis inghami n. sp. from the skeletal muscles of Opossums (Mammalia: Didelphidae) that were collected from south central Michigan (42° 43′-42° 79′N, 84° 18′-84° mathtype =" display ">6'W), USA. The new species is distinguished from all species described from North and South American Opossums by the distinctive morphology of the villar protrusions on the cyst wall. Sarcocysts of S. inghami are microscopic, up to 700 μm long and 110 μm wide. The sarcocyst wall is up to 7 μm thick, with long, stalked protrusions which average 5.5 × 1.2 μm. These are constricted at the base, expanded laterally, rounded off distally and occasionally bifid. The villar protrusions have numerous microtubules without electron−dense bodies that extend from the tips into the granular layer. Bradyzoites are 10.7 × 4.3 (8−−12 × 4−−5) μm. This is the second species of Sarcocystis sarcocyst described from the Virginia opossum in North America.