Sherril L. Green

Prevalence of Batrachochytrium dendrobatidis in Xenopus Collected in Africa (1871–2000) and in California (2001–2010)

International trade of the invasive South African clawed frog (Xenopus laevis), a subclinical carrier of the fungal pathogen Batrachochytrium dendrobatis (Bd) has been proposed as a major means of introduction of Bd into naïve, susceptible amphibian populations. The historical presence of Bd in the indigenous African population of Xenopus is well documented. However, there are no reports documenting the presence of Bd in wild Xenopus populations in the US, particularly in California where introduced populations are well-established after intentional or accidental release. In this report, a survey was conducted on 178 archived specimens of 6 species of Xenopus collected in Africa from 1871–2000 and on 23 archived specimens (all wild-caught Xenopus laevis) collected in California, USA between 2001 and 2010. The overall prevalence rate of Bd in the tested Xenopus was 2.8%. The earliest positive specimen was X. borealis collected in Kenya in 1934. The overall prevalence of Bd in the X. laevis collected in California was 13% with 2 positive specimens from 2001 and one positive specimen from 2003. The positive Xenopus (3/23) collected in California were collected in 2001 (2/3) and 2003 (1/3). These data document the presence of Bd-infected wild Xenopus laevis in California. The findings reported here support the prevailing hypothesis that Bd was present as a stable, endemic infection in Xenopus populations in Africa prior to their worldwide distribution likely via international live-amphibian trade.

The laboratory Xenopus sp.

Important Biological Features Introduction Habitat and Geography Behavior Anatomic and Physiologic Features General Features Integument Sensory Gastrointestinal and Excretory Reproduction Respiratory Cardiovascular Thermoregulation Longevity Aestivation References Husbandry Introduction Macroenvironment Microenvironment Housing Systems and Water Sources Static/Closed Systems Flow-Through Systems Modular/Recirculating Systems Filtration Systems and UV Water Sanitation Systems Mechanical Filtration Biological Filtration Chemical Filtration Ultraviolet Sterilization Water Quality Ph Alkalinity Temperature Conductivity Hardness Ammonia (Nh3) Nitrate and Nitrite Chlorine/Chloramines Dissolved Oxygen Total Dissolved Gases-Percent Saturation (TDG%) Carbon Dioxide Water Clarity Miscellaneous Water Toxicants Monitoring Water Quality Stocking Density Photoperiod Nutrition Types of Food Frequency of Feeding How Much to Feed Sanitation Environmental Enrichment Identification Transportation of Xenopus Record Keeping References Management Regulations and Regulatory Agencies Occupational Health and Safety: Injury and Zoonotic Risks References Veterinary Care Physical Examination Quarantine Clinical Problems Bacterial Infections Red Leg Syndrome Chryseobacterium (Formerly Called Flavobacterium) Spp Mycobacterium Spp Chlamydia Spp Viral Infections Ranavirus Lucke Herpesvirus Fungal Infections Batrachochytrium Dendrobatidis Saprolegnia Spp. and Other Water Molds Parasitic Infections Pseudocapillaroides Xenopi (Capillaria Xenopodis)Rhabdias (Strongyloid Lungworms) Cryptosporidia Acariasis (Mites) Noninfectious Diseases and Conditions Dehydration and Desiccation Gas Bubble Disease Chlorine/Chloramine Toxicities Neoplasia Rectal And Cloacal Prolapses Gout Skeletal Deformities Bite Wounds Ovarian Hyperstimulation Syndrome Thermal Shock Poor Egg Production, Poor Egg Quality Diagnosis of Infectious Diseases in Laboratory Xenopus General Comments on the Treatment of Infectious Diseases Treatment of General Trauma and Abrasions Anesthesia Tricaine Methanesulfonate (Ms-222) Benzocaine Gel Ketamine Eugenol (Clove Oil) Propofol Aseptic Surgery Analgesics and Post-Operative Care Euthanasia References Experimental Methodology Catching and Handling Xenopus Compound Administration Techniques Blood Sample Collection and Interpretation Blood Sample Collection Processing the Samples Xenopus Hemocytology: Characteristics Interpretation of the Hemogram And Serum Clinical Chemistries Egg/Oocyte Collection Surgical Laparotomy for Egg/Oocyte Harvest From Xenopus Raising Xenopus Tadpoles Necropsy Necropsy Equipment Necropsy Technique References Resources Organizations Electronic Resources Electronic Resources for X. Tropicalis Electronic Resources for X. Laevis Guidelines and Protocols For Harvesting Oocytes Additonal Guidelines Periodicals Books Vendor Contact Information Microchips Carriers Who Will Ship Xenopus Frog Suppliers (Frogs and Food) Modular Housing for Laboratory Xenopus Sanitation Supplies Water Quality Sensors Water Filtration Systems Water Test Kits (Spectrophotometric) Water Purifiers Taxonomy and Natural History Anatomy and Histology Physiology Ontogeny Genetics Medicine and Surgery Xenopus Listservs Index

Alterations in Cyclin-Dependent Protein Kinase 5 (CDK5) Protein Levels, Activity and Immunocytochemistry in Canine Motor Neuron Disease

Hereditary canine spinal muscular atrophy (HCSMA) is a dominantly inherited motor neuron disease in Brittany spaniels that is clinically characterized by progressive muscle weakness leading to paralysis. Histopathologically, degeneration is confined to motor neurons with accumulation of phosphorylated neurofilaments in axonal internodes. Cyclin-dependent kinase 5 (CDK5), a kinase related to the cell cycle kinase cdc2, phosphorylates neurofilaments and regulates neurofilament dynamics. We examined CDK5 activity, protein levels, and cellular immunoreactivity in nervous tissue from dogs with HCSMA, from closely age-matched controls and from dogs with other neurological diseases. On immunoblot analysis, CDK5 protein levels were increased in the HCSMA dogs (by ˜ 1.5-fold in both the cytosolic and the paniculate fractions). CDK5 activity was significantly increased (by ˜3-fold) in the paniculate fractions in the HCSMA dogs compared to all controls. The finding that CDK5 activity was increased in the young HCSMA homozygotes with the accelerated form of the disease, who do not show axonal swellings histologically, suggests that alterations in CDK5 occurs early in the pathogenesis, prior to the development of significant neurofilament pathology. Immunocytochemically, there was strong CDK5 staining of the nuclei, cytoplasm and axonal processes of the motor neurons in both control dogs and dogs with HCSMA. Further immunocytochemical studies demonstrated CDK5 staining where neurofilaments accumulated, in axonal swellings in the dogs with HCSMA. Our observations suggest phosphorylation-dependent events mediated by CDK5 occur in canine motor neuron disease.

Prevalence of Batrachochytrium dendrobatidis in 120 archived specimens of Lithobates catesbeianus (American bullfrog) collected in California, 1924-2007.

The chytrid fungus, Batrachochytrium dendrobatidis (Bd), has been identified as a major cause of the recent worldwide amphibian decline. Numerous species in North America alone are under threat or have succumbed to Bd-driven population extinctions. The American bullfrog (Lithobates catesbeianus) has been reported as a tolerant carrier of Bd. In this report, we used a qPCR assay to test 120 archived American bullfrog specimens collected between 1924 and 2007 in California, USA and Baja California, Mexico. The overall prevalence of Bd infection in this archived population of L. catesbeianus was 19.2%. The earliest positive specimen was collected in Sacramento County, California, USA in 1928 and is to date the earliest positive archived Bd specimen reported globally. These data demonstrate that Bd-infected wild amphibians have been present in California longer than previously known.

Dilative cardiomyopathy leading to congestive heart failure in a male squirrel monkey (Saimiri sciureus).

A 17‐year‐old, 1‐kg, colony‐housed, male squirrel monkey (Saimiri sciureus) developed clinical signs of congestive heart failure. The monkey presented with lethargy, increased heart and respiratory rates, and mild abdominal distention. The clinical history, laboratory analysis, and radiographic findings were consistent with heart failure due to dilative cardiomyopathy. Gross and microscopic examination of the heart confirmed a dilative cardiomyopathy. This is the first report describing congestive heart failure caused by dilative cardiomyopathy in a squirrel monkey. Spontaneous dilative cardiomyopathy may be infrequently observed in the squirrel monkeys because they are not routinely housed in the research environment during their advancing years.

Absence of mutations in the survival motor neuron cDNA from labrador retrievers with an inherited myopathy

The clinical phenotype of hereditary myopathy of labrador retrievers is consistent, but the pathological changes within muscle biopsy specimens can vary from type 1 fibre predominance (type 2 fibre deficiency) to dystrophic changes or overt neurogenic atrophy. The condition shares many clinical and pathological features with the mildest form of human childhood spinal muscular atrophy, and the survival motor neuron gene was therefore evaluated in dogs with the disease. Direct sequencing and comparisons of cDNA from the gene in seven labrador retrievers homozygous for the disease and four control dogs revealed no nucleotide mutations leading to changes in the deduced amino acid sequences. A single polymorphism was detected in two of the seven affected dogs, which was characterised by a nucleotide substitution at amino acid position 1155 within the non-coding 3’ untranslated region of exon 8. Northern blot analysis indicated that there were no differences in the steady state levels of mRNA from the gene of the affected labrador retrievers and control dogs.

Evolutionary perspectives into placental biology and disease.

In all mammals including humans, development takes place within the protective environment of the maternal womb. Throughout gestation, nutrients and waste products are continuously exchanged between mother and fetus through the placenta. Despite the clear importance of the placenta to successful pregnancy and the health of both mother and offspring, relatively little is understood about the biology of the placenta and its role in pregnancy-related diseases. Given that pre- and peri-natal diseases involving the placenta affect millions of women and their newborns worldwide, there is an urgent need to understand placenta biology and development. Here, we suggest that the placenta is an organ under unique selective pressures that have driven its rapid diversification throughout mammalian evolution. The high divergence of the placenta complicates the use of non-human animal models and necessitates an evolutionary perspective when studying its biology and role in disease. We suggest that diversifying evolution of the placenta is primarily driven by intraspecies evolutionary conflict between mother and fetus, and that many pregnancy diseases are a consequence of this evolutionary force. Understanding how maternal–fetal conflict shapes both basic placental and reproductive biology – in all species – will provide key insights into diseases of pregnancy.

Thermal shock in a colony of South African clawed frogs (Xenopus laevis)

occurs in adult horses with EGS. However, inconsistent with the foal having EGS is the absence of gastrointestinal stasis, a common feature of EGS (Cottrell and others 1999). Furthermore, while EGS almost invariably affects grazing horses (Doxey and others 1991), the owners reported that the foal had not grazed. EGS is also rare in suckling foals (Cottrell and others 1999), and acquired EGS has not previously been observed in foals less than four months old (E. Milne, personal communication) or five months old (K. Whitwell, personal communication). While transplacental transfer of the putative cause of EGS was proposed following identification ofsome neurodegenerative lesions associated with EGS in a foal which died 24 hours after delivery by caesarean section from a mare with acute EGS (Gilmour 1973a), this is unlikely to have happened in this case since the mare was clinically normal. Furthermore, Whitwell (1992) did not identify autonomic lesions in 12 fetuses from mares with EGS, and concluded that the causal agent of EGS does not cross the placenta. Examination of autonomic neurons from foals with confirmed toxicoinfectious botulism is warranted to further investigate the apparent link between toxicoinfectious botulism and EGS.