Dale McGinnity - Academia.edu (original) (raw)

Papers by Dale McGinnity

Theriogenology, 2015

We review the phylogeny, sperm competition, morphology, physiology, and fertilization environment... more We review the phylogeny, sperm competition, morphology, physiology, and fertilization environments, of the sperm of externally fertilizing fish and amphibians. Increased sperm competition in both fish and anurans generally increases sperm numbers, sperm length and their energy reserves. The difference between the internal osmolarity and iconicity of sperm cells and those of the aquatic medium control the activation, longevity, and velocity of sperm motility. Hypo-osmolarity of the aquatic medium activates the motility of freshwater fish and amphibian sperm and hyper-osmolarity activates the motility of marine fish sperm. The average longevity of the motility of marine fish sperm (~550 sec) was significantly (P<0.05) greater than that of freshwater fish sperm (~150 sec), with the longevities of both marine and freshwater fish being significantly (P<0.05) lower than that of anuran sperm (~4100 sec). The velocity of anuran sperm (25 µm/sec) was significantly (P<0.05) lower than the velocity of marine fish (140 µm/sec) or freshwater fish (135 µm/sec) sperm. The longevity of the sperm of giant salamanders (Cryptobranchoidea) of ~600 sec. was greater than that of freshwater fish sperm but much lower than anuran sperm. Our experiments and the literature showed that higher osmolarities promote greater longevity in anuran sperm, and some freshwater fish sperm, and that anuran and cryptobranchid sperm maintained membrane integrity long after the cessation of motility, demonstrating a sharing of energy reserves between motility and the maintenance of membrane integrity. The maintenance of the membrane integrity of anuran sperm in fresh water for up to 6 hrs showed an extremely high osmotic tolerance relative to fish sperm. The very high longevity and osmotic tolerance of anuran sperm and high longevity of cryptobranchid sperm, relative to those of freshwater fish, may reflect the complex fertilization history of amphibian sperm in general and anurans recent reversion from internal to external fertilization. Our findings provide a greater understanding of the reproductive biology of externally fertilizing fish and amphibians, and a biological foundation for the further development of reproduction technologies for their sustainable management.

Reproduction, fertility, and development, 2022

We review the use of reproduction technologies (RTs) to support the sustainable management of thr... more We review the use of reproduction technologies (RTs) to support the sustainable management of threatened Caudata (salamanders) and Gymnophiona (caecilian) biodiversity in conservation breeding programs (CBPs) or through biobanking alone. The Caudata include ∼760 species with ∼55% threatened, the Gymnophiona include ∼215 species with an undetermined but substantial number threatened, with 80% of Caudata and 65% of Gymnophiona habitat unprotected. Reproduction technologies include: (1) the exogenous hormonal induction of spermatozoa, eggs, or mating, (2) in vitro fertilisation, (3) intracytoplasmic sperm injection (ICSI), (4) the refrigerated storage of spermatozoa, (5) the cryopreservation of sperm, cell or tissues, (6) cloning, and (7) gonadal tissue or cell transplantation into living amphibians to eventually produce gametes and then individuals. Exogenous hormone regimens have been applied to 11 Caudata species to stimulate mating and to 14 species to enable the collection of sper...

Journal of aquatic animal health, 2021

Populations of the eastern hellbender Cryptobranchus alleganiensis alleganiensis have been declin... more Populations of the eastern hellbender Cryptobranchus alleganiensis alleganiensis have been declining for decades, and emerging pathogens and pesticides are hypothesized to be contributing factors. However, few empirical studies have attempted to test the potential effects of these factors on hellbenders. We simultaneously exposed subadult hellbenders to environmentally relevant concentrations of either Batrachochytrium dendrobatidis (Bd) or a frog virus 3-like ranavirus (RV), a combination of the pathogens, or each pathogen following exposure to a glyphosate herbicide (Roundup). Additionally, we measured the ability of the skin mucosome to inactivate Bd and RV in growth assays. We found that mucosome significantly inactivated RV by an average of 40% but had no negative effects on Bd growth. All treatments that included RV exposure experienced reduced survival compared to controls, and the combination of RV and herbicide resulted in 100% mortality. Histopathology verified RV as the c...

1. Sustainability America, Sarteneja, Corozal District, Belize.; 2. School of Life Sciences, East... more 1. Sustainability America, Sarteneja, Corozal District, Belize.; 2. School of Life Sciences, East China Normal University, 200062, Shanghai, P.R. China.; 3. Laboratory of Biology, Department of Regional Environment, Tottori University, Tottori 680-8551, Japan.; 4. Nashville Zoo, Nashville, Tennessee 37189, USA.; 5. Institute of Chinese giant salamander, Jishou University, P.R. China.; 6. Hiroshima City Asa Zoological Park, Hiroshima 731-3355, Japan. Japan Hanzaki Institute, Hyogo 679-3341, Japan.; 7. Douglas Kilpatrick, Umea University, 90736, Sweden.; 8. Collage of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA.; 9. Zoodirektoren. Germany, 47119 Duisburg, Landwehrstr, 32.; 10. Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo 108-8477, Japan.; 11. College of Veterinary Medicine, Sishuan Agricultural University, Wenjiang, Sichuan Province, 611130, P.R. China.

Russian Journal of Herpetology, 2011

More than 300 of the ~6180 known reptile species are critically endangered or endangered, with mo... more More than 300 of the ~6180 known reptile species are critically endangered or endangered, with more than 200 known amphibian species extinct, and ~1230 of the ~6800 known amphibian species are critically endangered or endangered. To assure the survival of these species conservation breeding programs (CBPs) are being established. The perpetuation of genetic variation is required in both CBPs and in natural populations, to maintain health and reproduction, and to enable adaptation to environmental change. However, over time genetic variation is often lost in CBPs and in small or fragmented natural populations. Reproduction technologies including gene banking through the use of sperm cryopreservation can perpetuate genetic variation. These technologies are being applied to amphibian conservation, however, their development and use for reptiles has received only sporadic attention. We review the use of reproduction technologies for the conservation of amphibians and reptiles including t...

Journal of Zoo and Wildlife Medicine, 2021

Abstract: Batrachochytrium dendrobatidis (Bd) is an important fungal pathogen present in wild hel... more Abstract: Batrachochytrium dendrobatidis (Bd) is an important fungal pathogen present in wild hellbender (Cryptobranchus alleganiensis) populations that appears to cause disease during novel exposure and acute stress. Hellbender repatriation efforts are ongoing to combat declining populations, but mortality by chytridiomycosis (disease from Bd) after release has been reported. The goal was to determine whether a safe antifungal agent could be administered and provide prolonged plasma concentrations without repeated handling. A subcutaneous implant impregnated with 24.5 mg of terbinafine was tested in three juvenile eastern hellbenders (C. a. alleganiensis) raised in human care, and plasma terbinafine concentrations were recorded from weekly to biweekly for 141 days. Plasma concentrations were variable, with peak plasma concentrations of 1,610, 112, and 66 ng/ml between 28 and 56 days postimplant. Although all hellbenders achieved plasma concentrations above the published minimum inhibitory concentration for terbinafine against Bd zoospores (63 ng/ml) at several time points, only one individual remained above this threshold for more than two consecutive time intervals. Results show the potential for these implants as a prophylaxis for chytridiomycosis in captive-to-wild hellbender releases. However, further investigation will be needed to determine the plasma concentrations required to achieve prophylaxis in vivo and implant reliability.

Reproduction, Fertility and Development, 2021

Semen of high to moderate quality was collected following the hormonal induction of North America... more Semen of high to moderate quality was collected following the hormonal induction of North American giant salamanders Cryptobranchus alleganiensis. Oocytes from one female yielded the first C. alleganiensis produced while maintained in aquaria under human care and the first externally fertilising salamander produced with cryopreserved spermatozoa and IVF. Further research is needed with North American giant salamanders to establish reliable techniques to produce large numbers of viable offspring, along with the application of cryopreserved spermatozoa.

Journal of Wildlife Diseases, 2020

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Amphibian and Reptile Conservation

The Chinese (Andrias davidianus) and Japanese (A. japonicus) giant salamanders far exceed any oth... more The Chinese (Andrias davidianus) and Japanese (A. japonicus) giant salamanders far exceed any other living amphibians in size, with the North American giant salamander (Hellbender; Cryptobranchus alleganiensis) also being one of the world’s largest amphibians. The sustainable management of cryptobranchids requires knowledge of cryptobranchid biogeography, ecology and reproduction in concert with other scientific fields. Cultural, political, and economic factors also contribute to the design of optimal strategies for sustainable management. Cryptobranchids are biologically similar in many ways including extreme longevity, a highly conserved morphology, low metabolism, males brooding of eggs, and large larvae. However, there are differences in cryptobranchids’ habitats and diets, reproductive behaviors and seasonality, fecundities, egg sizes, mating strategies and paternities. In “The giant salamanders (Cryptobranchidae): Part A” we reviewed cryptobranchid paleontology, phylogeny, gen...

Amphibian & reptile conservation

The Cryptobranchidae, commonly called the Giant Salamanders, are the largest surviving amphibians... more The Cryptobranchidae, commonly called the Giant Salamanders, are the largest surviving amphibians and comprise two extant genera, Andrias and Cryptobranchus. There are three cryptobranchid species, the Chinese giant salamander (Andrias davidianus; 180 cm, 59 kg), the Japanese giant salamander (A. japonicus; 155 cm, 55 kg), and the North American giant salamander(Cryptobranchus alleganiensis; 74 cm, 5.1 kg). Because of their iconic status as the world’s largest amphibians and their biopolitical significance, all cryptobranchids are subject to major and expanding initiatives for their sustainable management. Cryptobranchids are biologically similar in many ways; however, within these similarities there are differences in their habitats, diet, size, reproductive behavior and seasonality, fecundity and egg size, paternity, and growth and development. These characteristics are a consequence of their palaeontology, phylogeny, genetics, and morphology. Cryptobranchid conservation genetics ...

The order Caudata (salamanders and newts) comprise ~13% of the ~6,800 described amphibian species... more The order Caudata (salamanders and newts) comprise ~13% of the ~6,800 described amphibian species. Amphibians are the most threatened (~30% of species) of all vertebrates, and the Caudata are the most threatened (~45% of species) amphibian order. The fully aquatic Caudata family, the Cryptobranchidae (suborder Cryptobranchoidea), includes the the world's largest amphibians, the threatened giant salamanders. Cryptobranchids present particular survey challenges because of their large demographic variation in body size (from three cm larvae to 1.5 m adults) and the wide variation in their habitats and microhabitats. Consequently, a number of survey techniques (in combination) may be required to reveal their population and demography, habitat requirements, reproduction, environmental threats, and genetic subpopulations. Survey techniques are constrained by logistical considerations including habitat accessibility, seasonal influences, available funds, personnel, and equipment. Particularly with threatened species, survey techniques must minimize environmental disturbance and possible negative effects on the health of targeted populations and individuals. We review and compare the types and application of survey techniques for Cryptobranchids and other aquatic Caudata from a conservation and animal welfare perspective.

Journal of Chemical Ecology, 2013

Several lineages of brightly colored anurans independently evolved the ability to secrete alkaloi... more Several lineages of brightly colored anurans independently evolved the ability to secrete alkaloidcontaining defensive chemicals from granular glands in the skin. These species, collectively referred to as 'poison frogs,' form a polyphyletic assemblage that includes some species of Dendrobatidae, Mantellidae, Myobatrachidae, Bufonidae, and Eleutherodactylidae. The ability to sequester alkaloids from dietary arthropods has been demonstrated experimentally in most poison frog lineages but not in bufonid or eleutherodactylid poison frogs. As with other poison frogs, species of the genus Melanophryniscus (Bufonidae) consume large numbers of mites and ants, suggesting they might also sequester defensive alkaloids from dietary sources. To test this hypothesis, fruit flies dusted with alkaloid/nutritional supplement powder were fed to individual Melanophryniscus stelzneri in two experiments. In the first experiment, the alkaloids 5,8-disubstituted indolizidine 235B' and decahydroquinoline were administered to three individuals for 104 days. In the second experiment, the alkaloids 3,5disubstituted indolizidine 239Q and decahydroquinoline were given to three frogs for 153 days. Control frogs were fed fruit flies dusted only with nutritional supplement. Gas chromatography/mass spectrometry analyses revealed that skin secretions of all experimental frogs contained alkaloids, whereas those of all control frogs lacked alkaloids. Uptake of decahydroquinoline was greater than uptake of 5,8disubstituted indolizidine, and uptake of 3,5-disubstituted indolizidine was greater than uptake of decahydroquinoline, suggesting greater uptake efficiency of certain alkaloids. Frogs in the second experiment accumulated a greater amount of alkaloid, which corresponds to the longer duration and greater number of alkaloid-dusted fruit flies that were consumed. These findings provide the first experimental evidence that bufonid poison frogs sequester alkaloid-based defenses from dietary sources.

Theriogenology, 2019

Current rates of biodiversity loss pose an unprecedented challenge to the conservation community,... more Current rates of biodiversity loss pose an unprecedented challenge to the conservation community, particularly with amphibians and freshwater fish as the most threatened vertebrates. An increasing number of environmental challenges, including habitat loss, pathogens, and global warming, demand a global response toward the sustainable management of ecosystems and their biodiversity. Conservation Breeding Programs (CBPs) are needed for the sustainable management of amphibian species threatened with extinction. CBPs support species survival while increasing public awareness and political influence. Current CBPs only cater for 10% of the almost 500 amphibian species in need. However, the use of sperm storage to increase efficiency and reliability, along with an increased number of CBPs, offer the potential to significantly reduce species loss. The establishment and refinement of techniques over the last two decades, for the collection and storage of amphibian spermatozoa, gives confidence for their use in CBPs and other biotechnical applications. Cryopreserved spermatozoa has produced breeding pairs of frogs and salamanders and the stage is set for Lifecycle Proof of Concept Programs that use cryopreserved sperm in CBPs along with repopulation, supplementation, and translocation programs. The application of cryopreserved sperm in CBPs, is complimentary to but separate from archival gene banking and general cell and tissue storage. However, where appropriate amphibian sperm banking should be integrated into other global biobanking projects, especially those for fish, and those that include the use of cryopreserved material for genomics and other research. Research over a broader range of amphibian species, and more uniformity in experimental methodology, is needed to inform both theory and application. Genomics is revolutionising our understanding of biological processes and increasingly guiding species conservation through the identification of evolutionary significant units as the conservation focus, and through revealing the intimate relationship between evolutionary history and sperm physiology that ultimately affects the amenability of sperm to refrigerated or frozen storage. In the