Developing biological resource banks as a supporting tool for wildlife reproduction and conservation

A Method to Freeze Skin Samples for Cryobanks: A Test of Some Cryoprotectants for an Endangered Deer

The genetic diversity of endangered deer species, such as Mazama jucunda, can be preserved with the help of somatic cell cryopreservation. This procedure allows obtaining several cells from the individual even after its death, which is very important for applications in reproductive biotechnologies. This study's objective was to test cryopreservation protocols of skin fragments of M. jucunda, using different cryoprotectants in slow freezing. We evaluated four treatments, composed of three cryoprotectants, dimethyl sulfoxide (DMSO), polyvinylpyrrolidone (PVP), and ethylene glycol (EG), used alone and in combination. There was also a control group where the tissue did not undergo cryopreservation. Skin fragments were collected from the medial region of the pelvic limbs of three individuals. Each fragment was divided into 10 equal parts, standardized by weight, making two pieces for each treatment and control from each animal. The collected fragments were evaluated in culture, based on the speed of occupation of the free spaces of the cell culture flask. Cell viability was also evaluated using Trypan Blue dye and the mitotic index to understand the effect of toxicity and freezing on cell membrane integrity and cell division capacity, respectively. The treatments that used association with PVP proved to be more damaging to the cells, taking longer to reach confluence. EG alone showed better results than DMSO in the slow-freezing protocol. Clinical Trial Registration Number is 1390/21.

Establishment of Primary Adult Skin Fibroblast Cell Lines from African Savanna Elephants (Loxodonta africana)

Following population declines of the African savanna elephant (Loxodonta africana) across the African continent, the establishment of primary cell lines of endangered wildlife species is paramount for the preservation of their genetic resources. In addition, it allows molecular and functional studies on the cancer suppression mechanisms of elephants, which have previously been linked to a redundancy of tumor suppressor gene TP53. This methodology describes the establishment of primary elephant dermal fibroblast (EDF) cell lines from skin punch biopsy samples (diameter: ±4 mm) of African savanna elephants (n = 4, 14-35 years). The applied tissue collection technique is minimally invasive and paves the way for future remote biopsy darting. On average, the first explant outgrowth was observed after 15.75 ± 6.30 days. The average doubling time (Td) was 93.02 ± 16.94 h and 52.39 ± 0.46 h at passage 1 and 4, respectively. Metaphase spreads confirmed the diploid number of 56 chromosomes. The successful establishment of EDF cell lines allows for future elephant cell characterization studies and for research on the cancer resistance mechanisms of elephants, which can be harnessed for human cancer prevention and treatment and contributes to the conservation of their genetic material.

Postmortem Collection of Gametes for the Conservation of Endangered Mammals: A Review of the Current State-of-the-Art

The collection of gametes from recently deceased domestic and wildlife mammals has been well documented in the literature. Through the utilization of gametes recovered postmortem, scientists have successfully produced embryos in 10 different wildlife species, while in 2 of those, offspring have also been born. Thus, the collection of gametes from recently deceased animals represents a valuable opportunity to increase genetic resource banks, obviating the requirement for invasive procedures. Despite the development of several protocols for gamete collection, the refinement of these techniques and the establishment of species-specific protocols are still required, taking into account both the limitations and the opportunities. In the case of wildlife, the optimization of such protocols is impeded by the scarcity of available animals, many of which have a high genetic value that must be protected rather than utilized for research purposes. Therefore, optimizing protocols for wildlife species by using domestic species as a model is crucial. In this review, we focused on the current advancements in the collection, preservation, and utilization of gametes, postmortem, in selected species belonging to Equidae, Bovidae, and Felidae, both domestic and wildlife.

Mitochondria-targeted antioxidant MitoQ ameliorates ROS production and improves cell viability in cryopreserved buffalo fibroblasts

Cryopreservation commonly decreases the cellular functionality and post-thaw viability of cells. Reactive oxygen species (ROS) generated during cryopreservation degrade mitochondrial activity and promote the release of cytochrome C which activates caspases required for apoptosis. Antioxidants have the potential to improve the recovery efficiency of cells by reducing ROS production and maintaining mitochondrial membrane potential (MMP). The present study was conducted to explore the role of MitoQ, a derivative of coenzyme Q10 on cryopreserved fibroblasts derived from buffalo skin. To achieve our goal, buffalo skin fibroblasts were treated with varying concentrations of MitoQ (0, 0.1, 0.5, 1, 2, and 10 μM) for 24, 48, and 72 h. The MMP, ROS generation, cell viability was measured by flow cytometry. Furthermore, expression of genes related to mitochondrial oxidative stress (NRF2, GPX, and SOD), apoptosis (BAK and caspase 3) and cell proliferation (AKT) were also assessed. The results showed that over a period of 72 h lower concentrations of MitoQ (0.1-0.5 μM) decrease the ROS production, improves MMP and cell viability whilst the high concentration of MitoQ (2-10 μM) increased the oxidative damage to the cells. Taken together, our study provide important insights into the novel role of MitoQ in cryopreserved buffalo skin fibroblasts. In conclusion, we demonstrated the dose-dependent functional role of MitoQ on cryopreserved fibroblasts for improving post-thaw cell viability and cellular function.

Biobanking and use of gonadal tissues - a promising strategy for conserving wildlife from the Caatinga biome

Biological Resource Banks (BRB) or Genetic Resource Banks (GRB) are critical tools for the conservation of animal biodiversity. According to the International Union for Conservation of Nature, more than 38,500 species are threatened with extinction, out of a total of 138,300 surveyed species. These banks are repositories of biological samples and data recovered and preserved for the long term by zoos, universities, research centers and other conservation organizations. In recent years, BRB have increasingly included ovarian and testicular tissues as additional options to rescue and propagate wild species, especially those at risk of extinction. After in vitro culture or grafting, gonadal tissues are potential sources of matured gametes that can be used for Assisted Reproduction Technologies while informing about gametogenesis or mechanisms involved in infertility. It therefore is crucial to properly recover, cryopreserve, and culture these tissues using species-specific protocols. Developing BRBs is currently one of the strategies to preserve species from the Caatinga biome - an exclusively Brazilian biome with a rich wild fauna that suffers from anthropogenic activities. Among wild species from this biome, studies have been primarily conducted in collared peccaries, agoutis, cavies, and armadillos to preserve their ovarian and testicular tissues. Additionally, domestic species such as the domestic cat and donkeys have been proposed as models for wild species that are phylogenetically close. This review addresses the main technical aspects involved in obtaining BRB derived from gonadal tissues in some wild species of the Caatinga biome. It reports recent advances and perspectives to use these biological materials for wildlife conservation.

Microenvironment factors promoting the quality of vitrified cat oocytes

In oocyte cryopreservation programs, vitrification has overthrown conventional slow freezing both in veterinary and human medicine. In animals, its feasibility in field conditions makes it the preferred technique for the safeguard of genetic resources from zoo or wild animals, including threatened felids, for which the domestic cat is an excellent model. However, many cellular injuries, such as cytoskeleton, mitochondria and meiotic spindle alterations, DNA damage, zona pellucida hardening and cumulus cell loss, might occur following vitrification. After warming, although the exact mechanisms are still unclear, degeneration is a frequent outcome for cat vitrified oocytes. For immature (germinal vesicle) gametes, in vitro maturation after warming is a challenge, and cleavage after fertilization barely reaches 15-30%, while for mature (metaphase II) cryopreserved gametes it can get to 30-50%. Anyway, the progression to late embryos stages is often impaired, and improvements are needed. Standard cryopreservation protocol and the use of conventional in vitro culture systems after warming may not be enough for vitrified oocytes to recover and demonstrate their full developmental potential. Physical or chemical factors applied to oocytes undergoing vitrification, as an enrichment to the vitrification step, or to the culture microenvironment, could create more favorable conditions and promote vitrified oocyte survival and development. From the use of three-dimensional culture systems to the regulation of metabolic activities and cellular pathways, this review aims to explore all the possibilities employed so far, including the studies performed by our own lab, and the future perspectives, to present the most effective strategies for cat oocyte vitrification and the best time for their application (i.e., before, during, or after vitrification-warming).

How Can We Introduce ART into Wild Felid Conservation in Practice? Joint Experience in Semen Collection from Captive Wild Felids in Europe

Simple Summary

Artificial reproductive techniques (ART), such as cryopreservation of sperm cells and artificial insemination, are useful tools for species conservation. However, there is relatively little information published about their introduction into clinical practice for wild felids. The aim of this paper was to describe how those techniques were applied by three European teams in various species of wild felids. In total, this article presents 22 semen collection attempts in 12 species of wild felids, 15 of which were successful and resulted in the collection of at least one million spermatozoa. The failures in obtaining spermatozoa were most probably due to (1) male infertility, (2) wrong age/non-breeding season, or (3) recent multiple copulations. The cases presented in the article confirm that although ART have been introduced into clinical practice, they are mostly used in cases of infertility, not as routine breeding tools. Greater involvement of zoological gardens and private breeders is required, as many chances for preservation of valuable material are lost.

Abstract

Although artificial reproductive techniques (ART) are considered to be a valuable tool for species conservation, information about their introduction into clinical practice for wild felids is limited. The aim of this paper was to jointly describe cases of non-experimental sperm collection from males of various species of wild felids, performed by three European centers focused on feline reproduction. In total, the article presents 22 attempts of semen collection in 12 species of wild felids. The reasons for semen collection were: fertility assessment (10 cases), artificial insemination (5 cases), sperm rescue (postmortem collection for cryopreservation, 5 cases), and sperm banking (in vivo collection for cryopreservation, 2 cases). Semen collection was successful (defined as at least 1 × 10⁶ spermatozoa) in 15 cases. The failures in obtaining spermatozoa were most probably due to (1) male infertility, (2) wrong age/non-breeding season, or (3) recent multiple copulations. The cases presented here confirm that although ART have been introduced into clinical practice, they are mostly used in cases of infertility, not as routine breeding tools. Higher involvement of zoological gardens and private breeders is required, as many chances for preservation of valuable material are lost.

Morphological, Ultrastructural, and Immunocytochemical Characterization and Assessment of Puma (Puma concolor Linnaeus, 1771) Cell Lines After Extended Culture and Cryopreservation

Cell lines are valuable tools to safeguard genetic material from species threatened with extinction that is mainly due to human action. In this scenario, the puma constitutes a species whose population is being rapidly reduced in the ecosystems it inhabits. For the first time, we characterized puma skin-derived cell lines and assessed these cells after extended culture (experiment 1) and cryopreservation (experiment 2). Initially, we identified and characterized four dermal fibroblast lines using morphology, ultrastructure, and immunofluorescence assays. Moreover, we evaluated the effects of culture time (1st, 3rd, and 10th passages) and cryopreservation on their morphology, ultrastructure, viability, metabolism, proliferative activity, reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm), and apoptosis. The cells showed a typical spindle-shaped morphology with centrally located oval nuclei. The cells were identified as fibroblasts by staining for vimentin. In vitro culture after the 1st, 3rd, and 10th passages did not alter most of the evaluated parameters. Cells in the 3rd and 10th passages showed a reduction in ROS levels (p < 0.05). The ultrastructure revealed morphological damage in the prolongments, and nuclei of cells derived from the 3rd and 10th passages. Moreover, cryopreservation resulted in a reduction in ΔΨm compared with that of noncryopreserved cells, suggesting that the optimization of cryopreservation methods for puma fibroblasts is essential. In conclusion, we found that viable fibroblasts could be obtained from puma skin, with slight changes after the 10th passage in in vitro culture and cryopreservation. This is the first report on the development of cell lines derived from pumas.

Assessment of thawed sperm quality from feline species: Ocelot (Leopardus pardalis) and oncilla (Leopardus gutullus)

This study aimed to evaluate the cryopreservation effects on the semen of oncilla (Leopardus guttulus, n = 5, 15 ejaculates) and ocelot (Leopardus pardalis, n = 5, 17 ejaculates) and compare two extenders (commercial and non-commercial extender). An andrological exam was conducted (testicle measurements and penis evaluation), including semen collection by electroejaculation. After collection, the semen was assessed to volume, color, pH, sperm motility, vigor, sperm number in the ejaculate, viability, membrane integrity, and sperm morphology. Samples were centrifuged (300 g for 10 min) and pellet diluted in two extenders (TRIS/glucose/egg yolk and BotuCRIO®), packed into 0.25 mL French straws (20 × 10⁶ spermatozoa/mL), equilibrated at 5 °C for 1 h (<0.5 °C/min), freezing in nitrogen vapor for 20 min. Thawing was achieved at 46 °C for 15 min. Thawed samples were evaluated to the same characteristics and ultrastructural analysis. There is no difference for extenders, but in ocelot the spermatozoa maintained higher quality after thawing. Major defects were increased in thawed samples, especially acrosome injuries, in both species. Semen contamination by urine was remarkable to oncilla (53% of the ejaculates) which can have reduced sperm cryoresistance of this species. Ultrastructural analysis endorsed morphological analysis under light microscopy and identified cells with acrosome vesiculation. In conclusion, the spermatozoa of ocelot were more cryoresistent and the extender commercial and non-commercial were suitable for their cryopreservation. Other extenders should be investigated for oncilla.

Effects of somatic tissue cryopreservation on puma (Puma concolor L, 1771) tissue integrity and cell preservation after in vitro culture

Somatic resource banks play a crucial role in the conservation of genetic diversity, allowing for the preservation of biological samples from different populations. Puma somatic cells can be recovered from these banks and used in assisted techniques toward enhancing their multiplication and conservation. In response to the population reduction of this ecologically importance species, we aimed to evaluate the capacity of cryopreservation of somatic tissues on the maintenance of the integrity and quality of the cells recovered after culture, with the aim of establishing a somatic tissue bank that will allow for the safeguarding of a wide genetic sampling of pumas. Cryopreservation increased the thickness of the corneum layer in the tissues, and the number of perinuclear halos and empty gaps. Nevertheless, cryopreservation was able to maintain normal fibroblast patterns, even showing an increase in the percentage of collagen fibers. Cryopreservation maintained the proliferative potential of the tissues and the parameters evaluated during in vitro culture, mainly regarding the viability, proliferative activity, and apoptosis levels. Nevertheless, cells from cryopreserved tissues showed decreased metabolism and mitochondrial membrane potential when compared to cells from non-cryopreserved tissues. In summary, we demonstrated for the first time that puma somatic tissues subjected to cryopreservation are viable and maintain tissue integrity, featuring minimal changes after warming. Although viable somatic cells are obtained from these tissues, they undergo alterations in their metabolism and mitochondrial membrane potential. Improvements in the conservation conditions of somatic samples are needed to increase the quality of somatic tissue banks in this species.

Somatic feather follicle cell culture of the gallus domesticus species for creating a wild bird genetic resource bank

The creation of a genetic resource bank of avian species aims to prevent the decline and fragmentation of wild bird populations, which in turn lead to the loss of genetic diversity and, in more serious cases, the extinction of the most threatened species. In order for the collected genetic material to be stored in a bank and useful when necessary, it is essential to improve the technique ensuring its effectiveness. Thus, our study used feather follicle cells from the domestic gallus species to standardize the technique of cell culture and subsequent cryopreservation. This study aimed to establish a protocol, in vitro, of isolation and primary culture of somatic cells derived from the feather follicle, with the purpose of establishing a cell lineage, and evaluate its viability for the biobank formation. Developing feathers of gallus domesticus were collected at 12, 21 and 34 days of age. The feathers were morphologically analyzed and then we selected the region of the calamus due to the presence of pulp for cell culture and cryopreservation. The results showed that it is possible to find cells with distinct morphology; cells in elliptical shape with central nucleus also in elliptical shape, cells with shape and round nucleus, cells compatible with the fibers of the barbules, cell agglomerates and cells adhered to the bottom of the plate with fibroblastatoid shape. After 24 hours of culture there was the presence of primary culture with 80% of confluence and after cryopreservation the average viability after freezing was 68.8%, with cellular morphologies being maintained. Therefore, we proved the isolation of somatic cells from the follicle of bird's feathers, suggesting that this is a source of great value, viable and effective for obtaining biological material for the elaboration of a biobank.

Isolation, characterization, and cryopreservation of collared peccary skin-derived fibroblast cell lines

Background

Biobanking of cell lines is a promising tool of support for wildlife conservation. In particular, the ability to preserve fibroblast cell lines derived from collared peccaries is of significance as these wild mammals are unique to the Americas and play a large role in maintaining the ecosystem. We identified collared peccary fibroblasts by immunofluorescence and evaluated their morphology, growth and adherence capacity. Further, we monitored the viability and metabolic activity of the fibroblasts to determine the effects of passage number and cryopreservation on establishment of cell lines.

Methods

Skin biopsies were collected from the peripheral ear region from five adult animals in captivity. Initially, cells were isolated from fragments and cultured in the Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum and 2% antibiotic-antimycotic solution under a controlled atmosphere (38.5 °C, 5% CO₂). We evaluated the maintenance of primary cells for morphology, adherence capacity of explants, explants in subconfluence, cell growth and absence of contamination. Moreover, we identified the fibroblast cells by immunofluorescence. Additionally, to evaluate the influence of the number of passages (first, third and tenth passage) and cryopreservation on establishment of cell lines, fibroblasts were analysed for the viability, metabolic activity, population doubling time (PDT), levels of reactive oxygen species (ROS), and mitochondrial membrane potential (ΔΨm).

Results

All explants (20/20) adhered to the dish in 2.4 days ± 0.5 with growth around the explants in 4.6 days ± 0.7, and subconfluence was observed within 7.8 days ± 1.0. Moreover, by morphology and immunocytochemistry analyses, cells were identified as fibroblasts which presented oval nuclei, a fusiform shape and positive vimentin staining. No contamination was observed after culture without antibiotics and antifungals for 30 days. While there was no difference observed for cell viability after the passages (first vs. third: P = 0.98; first vs. tenth: P = 0.76; third vs. tenth: P = 0.85), metabolic activity was found to be reduced in the tenth passage (23.2 ± 12.1%) when compared to that in the first and third passage (100.0 ± 24.4%, P = 0.006). Moreover, the cryopreservation did not influence the viability (P = 0.11), metabolic activity (P = 0.77), or PDT (P = 0.11). Nevertheless, a greater ΔΨm (P = 0.0001) was observed for the cryopreserved cells (2.12 ± 0.14) when compared to that in the non-cryopreserved cells (1.00 ± 0.05). Additionally, the cryopreserved cells showed greater levels of intracellular ROS after thawing (1.69 ± 0.38 vs. 1.00 ± 0.22, P = 0.04).

Conclusions

This study is the first report on isolation, characterization and cryopreservation of fibroblasts from collared peccaries. We showed that adherent cultures were efficient for obtaining fibroblasts, which can be used as donor cells for nuclei for species cloning and other applications.

Investigation on revascularization time and initial damage after transplantation of fresh and cryopreserved ovarian tissue in domestic cats

The present study evaluated revascularization time of fresh and cryopreserved cat ovarian tissue after transplantation to subcutaneous tissue. Ovaries of five cats were used and eight pieces of ovarian tissue were taken from each pair of ovaries. Immediately after removal, three pieces were transplanted and one fixed for fresh control. The remaining four pieces were cryopreserved and, after thawing, one was fixed for cryopreservation control and three were transplanted. Grafts were recovered on days 2 (D2), 4 (D4) and 6 (D6) post-transplantation. Blood vessels were identified by immunohistochemistry and doppler ultrasound. Immunohistochemistry showed that the percentages of total tissue area occupied by blood vessels were similar (P > 0.05) in fresh and cryopreserved tissues. In both cases, blood vessel area was significantly higher (P < 0.05) on D4 and D6 compared to D0. Ultrasound analysis showed vascularization improvement on the periphery of grafts from D2 to D4 and from D4 to D6, both in fresh and cryopreserved tissue samples. Nonetheless, there was a significant decrease (P < 0.05) in the percentage of morphologically normal follicles (MNF) after transplantation compared to non-transplanted tissue (D0), both for fresh and cryopreserved samples. Moreover, the number of follicles found in samples was considerably smaller after grafting. In conclusion, revascularization of ovarian tissue autotransplanted to subcutaneous tissue in domestic cats occurs within 4 days after transplantation, both for fresh and cryopreserved tissue. However, large follicular loss has been observed in the first days post-transplantation, especially in cryopreserved tissues.

Cryopreservation and Culture of Testicular Tissues: An Essential Tool for Biodiversity Preservation

Systematic cryo-banking of reproductive tissues could enhance reproductive management and ensure sustainability of rare mammalian genotypes. Testicular tissues contain a vast number of germ cells, including at early stages (spermatogonia and spermatocytes), that can potentially develop into viable spermatozoa after grafting or culture in vitro, and the resulting sperm cells then can be used for assisted reproductive techniques. The objective of this review was to describe current advances, limitations, and perspectives related to the use of testicular tissue preservation as a strategy for the conservation of male fertility. Testes can be obtained from mature or prepubertal individuals, immediately postmortem or by orchiectomy, but testicular biopsies could also be an alternative to collect samples from living individuals. Testicular fragments can be then cryopreserved by using slow or ultra-rapid freezing, or even vitrification methods. The composition of cryopreservation media can vary according to species-specific characteristics, especially regarding the cryoprotectant type and concentration. Finally, spermatozoa have been usually obtained after xenografting of testicular fragments into severely immunodeficient mice, while this method still has to be optimized after in vitro culture conditions.

Characteristics of Mesenchymal Stem Cells Isolated from the Bone Marrow of Red Pandas

Mesenchymal stem cells (MSC) have strong therapeutic potential due to their capacity for self-renewal and multilineage differentiation. MSCs can also be useful in preserving the current genetic diversity of endangered wildlife. To date, MSCs from various species have been studied, but only a few species of endangered wild animals have been reported. Adult bone marrow (BM) is a rich source of mesenchymal stem cells. The aim of this study was to isolate and characterize MSCs derived from the BM of red pandas. Red panda BM-MSCs isolated from five individuals were fibroblast-like cells, similar to other species. Cultured BM-MSCs with normal karyotype were negative for the hematopoietic line marker CD34 and the endothelial cell marker CD31 but were positive for MSC markers, including CD44, CD105 and CD90. RT-PCR and western blot analysis showed self-renewal and pluripotency genes, including Oct4, Sox2 and Klf4, were also expressed in red panda BM-MSCs. Finally, red panda BM-MSCs had the potential for differentiation into osteogenic, adipogenic and neuron-like cells by using a combination of previously reported protocols for other species. We have therefore demonstrated that cells harvested from red panda bone marrow are capable of extensive in vitro multiplication and multilineage differentiation, which is an essential step toward their use in the preservation of red pandas biological diversity and future studies on MSC applications in endangered species.

Establishment and cryopreservation of a cell line derived from caudal fin of endangered catfish Clarias dussumieri Valenciennes, 1840

We describe a new cell line, Clarias dussumieri fin (ClDuF), from the caudal fin of C. dussumieri using the explant technique followed by cryopreservation. The cryopreserved CiDuF cells were validated for quality and other characteristics. They showed typical epithelial morphology in vitro and epithelial cells outgrew their fibroblast cells after the fifth passage. ClDuF cells had a characteristic sigmoid curve with population doubling in 24 h. Immunotyping of the ClDuF cells against cytokeratin suggested the epithelial lineage. Chromosome analysis showed normal diploid (2n = 50) numbers and the cells did not contain any contamination, including Mycoplasma and other microbes. Partial sequencing of fragments of mitochondrial 16s rRNA and COI genes of ClDuF confirmed that the cell line was initiated from C. dussumieri. Cells at the 10th and 25th passages had more than 80% and 70% viability in the culture, respectively, after 6 months of storage at LN₂ . These ClDuF cells were morphologically identical to the cells before freezing and the genetic resource of C. dussumieri was preserved. The species-specific cells can serve as a valuable source for virus isolation, conservation and cloning of somatic cells.

Potential role of intraspecific and interspecific cloning in the conservation of wild mammals

Intraspecific and interspecific cloning via somatic cell nuclear transfer (iSCNT) is a biotechnique with great possibilities for wild mammals because it allows the maintenance of biodiversity by recovering species, nuclear reprogramming for the production of pluripotency-induced cells, and studies related to embryonic development. Nevertheless, many areas in cloning, especially those associated with wild mammals, are still in question because of the difficulty in obtaining cytoplasmic donor cells (or cytoplasts). Conversely, donor cell nuclei (or karyoplasts) are widely obtained from the skin of living or post-mortem individuals and often maintained in somatic cell banks. Moreover, the creation of karyoplast–cytoplast complexes by fusion followed by activation and embryo development is one of the most difficult steps that requires further clarification to avoid genetic failures. Although difficult, cloning different species, such as wild carnivores and ungulates, can be successful via iSCNT with embryo development and the birth of offspring. Thus, novel research in the area that contributes to the conservation of biodiversity and knowledge of the physiology of species continues. The present review presents the failures and successes that occurred with the application of the technique in wild mammals, with the goal of helping future work on cloning via iSCNT.

Strong Heterogeneity in Advances in Cryopreservation Techniques in the Mammalian Orders

Between 1970 and 2012, vertebrate abundance has declined by 58% with an average annual decline of 2%, calling for serious action to prevent a mass extinction and an irreversible loss of biodiversity. Cryobanks and cryopreservation have the potential to assist and improve ex situ and in situ conservation strategies by storing valuable genetic material. A great deal of studies concerning cryopreservation have been performed within the class Mammalia, although no systematic overview has previously been presented. The objective of this study is therefore to evaluate the status, pattern and future of cryopreservation within Mammalia. A strong disproportional distribution of studies in examined orders is displayed. For the majority of examined orders less than 10% of species has been examined. However, the cryopreservation of germplasm has in several cases been successful and resulted in successful applications of assisted reproductive techniques (ARTs). Various obstacles are associated with the development of cryopreservation protocols, and among them the most prominent is interspecific differences in cryotolerance. Extrapolation of protocols in closely related species is considered the most applicable procedure, and a future supplement to overcome this problem is the examination and comparison of cryobiological traits. Successful protocols have been developed for the vast majority of domesticated mammals, which gives incentive for the further extrapolation of protocols in threatened species.

Establishment of a Somatic Cell Bank for Indian Buffalo Breeds and Assessing the Suitability of the Cryopreserved Cells for Somatic Cell Nuclear Transfer

Biobanks of cryopreserved gametes and embryos of domestic animals have been utilized to spread desired genotypes and to conserve the animal germplasm of endangered breeds. In principle, somatic cells can be used for the same purposes, and for reviving of animals, the somatic cells must be suitable for animal cloning techniques, such as somatic cell nuclear transfer. In the present study, we derived and cryopreserved somatic cells from three breeds of riverine and swamp-like type buffaloes and established a somatic cell bank. In total, 350 cryovials of 14 different individual animals (25 cryovials per animal) were cryopreserved and informative data such as breed value, origin, and others were documented. Immunostaining of the established cells against vimentin and cytokeratin suggested a commitment to the fibroblast lineage. In addition, microsatellite analysis was performed and documented for unambiguous parentage verification of clones in the future. Subsequently, the cryopreserved cells were tested for their suitability as nuclear donors (n = 7) using handmade cloning, and the reconstructed embryos were cultured in vitro. The cleavage rates (95.99% ± 2.17% vs. 82.18% ± 2.50%) and blastocyst rates (37.73% ± 1.54% vs. 24.31% ± 1.78%) were higher (p < 0.05) for riverine buffalo cells than that of swamp-like buffalo cells, whereas the total cell numbers of blastocysts (258.16 ± 36.25 vs. 198.16 ± 36.25, respectively) were similar. In conclusion, we demonstrated the feasibility of biobanking of buffalo somatic cells, and that the cryopreserved cells can be used to produce cloned embryos. This study encourages the development of somatic cell biobanks of domestic livestock, including endangered breeds of buffalo, to preserve valuable genotypes for future revitalization by animal cloning techniques.

Isolation and preservation of multipotent mesenchymal stem cells from bone marrow of Arabian leopard (Panthera pradus nimr)

The Arabian leopard (Panthera pardus nimr) is critically endangered by the International Union for Conservation of Nature, with an effective population of 150-250 across its entire range in the Arabian Peninsula. Isolation and preservation of multipotent mesenchymal stem cells is beneficial both for medical and research purposes. The optimal protocol for collection, handling, culturing and preserving the Arabian leopard mesenchymal stem cells acquired from bone marrow was established. Anesthesia with combination of medetomidine and tiletamine-zozalepam is the safest option even for old animals with concurrent disease including chronic kidney disease.

Cat ovarian follicle ultrastructure after cryopreservation with ethylene glycol and dimethyl sulfoxide

Ovarian tissue cryopreservation is a promising technique for fertility maintenance. The aim of this study was to compare the morphology of domestic cat ovarian follicles after tissue cryopreservation with ethylene glycol (EG) and dimethyl sulfoxide (Me₂SO). Ovaries from healthy adult cats undergoing elective ovariohysterectomy were used. Eight fragments were obtained from each pair of ovaries: two were used as fresh controls; three were submitted to fresh perfusion toxicity test and perfused with M199, 10% fetal calf serum and 0.4% sucrose containing Me₂SO 1.5 M, EG 1.5 M or Me₂SO 0.75 M + EG 0.75 M; and the remaining three fragments were perfused as described and submitted to slow freezing. After 45 days of cryopreservation, the samples were thawed, fixed and processed for light and transmission electron microscopy (TEM). The percentages of morphologically normal follicles identified by light microscopy were higher in the control group (94.45%) in comparison to the frozen groups (80.56% with EG, 78.7% with Me₂SO and 75.87% with EG + Me₂SO). The fresh perfused tissue showed no statistical difference compared to control or frozen samples. The TEM analysis showed less damage in the ultrastructure of follicles from the Me₂SO group in comparison with the EG and Me₂SO + EG groups. According to the morphological analysis, 1.5 M Me₂SO is the best cryoprotectant for cryopreservation of domestic cat ovarian tissue regarding the morphology of preantral follicles after thawing. Further studies regarding the viability of these follicles should be performed.

Use of somatic cell banks in the conservation of wild felids

The conservation of biological resources is an interesting strategy for the maintenance of biodiversity, especially for wild felids who are constantly threatened with extinction. For this purpose, cryopreservation techniques have been used for the long-term storage of gametes, embryos, gonadal tissues, and somatic cells and tissues. The establishment of these banks has been suggested as a practical approach to the preservation of species and, when done in tandem with assisted reproductive techniques, could provide the means for reproducing endangered species. Somatic cell banks have been shown remarkable for the conservation of genetic material of felids; by merely obtaining skin samples, it is possible to sample a large group of individuals without being limited by factors such as gender or age. Thus, techniques for somatic tissue recovery, cryopreservation, and in vitro culture of different wild felids have been developed, resulting in a viable method for the conservation of species. One of the most notable conservation programs for wild felines using somatic samples was the one carried out for the Iberian lynx, the most endangered feline in the world. Other wild felids have also been studied in other continents, such as the jaguar in South America. This review aims to present the technical progress achieved in the conservation of somatic cells and tissues in different wild felids, as well address the progress that has been achieved in a few species.

Establishment and characterization of pygmy killer whale (Feresa attenuata) dermal fibroblast cell line

The pygmy killer whale (Feresa attenuata) (PKW) is a tropical and subtropical marine mammal commonly found in the Atlantic, Indian and Pacific oceans. Since the PKWs live in offshore protected territories, they are rarely seen onshore. Hence, PKW are one of the most poorly understood oceanic species of odontocetes. The dermal tissue comes primarily from stranding events that occur along the coast of the Shantou, Guangdong, China. The sampled tissues were immediately processed and attached on collagen-coated 6-well tissue culture plate. The complete medium (DMEM and Ham’s F12, fetal bovine serum, antibiotic and essential amino acids) was added to the culture plates. The primary culture (PKW-LWH) cells were verified as fibroblast by vimentin and karyotype analyses, which revealed 42 autosomes and two sex chromosomes X and Y. Following transfection of PKW-LWH cells with a plasmid encoding, the SV40 large T-antigens and the transfected cells were isolated and expanded. Using RT-PCR, western blot, immunofluorescence analysis and SV40 large T-antigen stability was confirmed. The cell proliferation rate of the fibroblast cells, PKW-LWHT was faster than the primary cells PKW-LWH with the doubling time 68.9h and 14.4h, respectively. In this study, we established PKW dermal fibroblast cell line for the first time, providing a unique opportunity for in vitro studies on the effects of environmental pollutants and pathogens that could be determined in PKW and/or Cetaceans.

Influence of Cryopreservation Solution on the In Vitro Culture of Skin Tissues Derived from Collared Peccary (Pecari tajacu Linnaeus, 1758)

Skin vitrification is a promising and alternative tool for the conservation of biodiversity, especially for wild mammals, such as collared peccaries. Several factors can affect the success of this procedure, such as the cryoprotectant solution used. Therefore, this study was carried out to compare the efficiency of various vitrification solutions for recovery of viable cells after in vitro culture of cryopreserved skin tissues derived from the collared peccary, aiming to study the application in biobanking, where cellular use is not immediately required. Then, Dulbecco's modified Eagle's medium (DMEM) composed of 2.2 g/L sodium bicarbonate and 10% fetal bovine serum (FBS) was supplemented with 3.0 M ethylene glycol (EG) or 3.0 M dimethyl sulfoxide (DMSO) or 1.5 M EG plus 1.5 M DMSO with or without sucrose (SUC; 0.25 M) to produce six solutions for solid-surface vitrification. After warming, skin tissues were cultured in vitro and recovered cells were analyzed for morphology, adhesion, subconfluence, and proliferative activity for developing the growth curve and determining the population doubling time (PDT), and viability by Trypan Blue. The vitrification did not alter the ability of the tissues to adhere to the culture dish, as well as the day of all explants with cell growth, subconfluence samples, subconfluence total time, and PDT (p > 0.05). Moreover, independent of the cryoprotectant solution used, the vitrification altered the day of all attached explants (p < 0.05). Nevertheless, for viability after the first passage, only the EG-SUC (86.9%) and DMSO-SUC (91.4%) groups maintained viable cell recovery similar to the nonvitrified group (96.3%, p > 0.05). Additionally, for viability after the third passage, only the EG-SUC group maintained the cell quality (88.3%), when compared with the nonvitrified (97.8%, p > 0.05). In conclusion, DMEM with 10% FBS, 3.0 M EG, and 0.25 M sucrose was the most efficient solution for vitrifying collared peccary skin tissues, leading to the in vitro culture of viable cells.

Caracterização histomorfológica do sistema tegumentar auricular de cateto - Pecari tajacu Linnaeus, 1758)

RESUMO A criopreservação de tecido somático derivado da pele de catetos consiste numa alternativa para a conservação da biodiversidade por meio da associação com a transferência nuclear. Nesse contexto, a manipulação de tecidos da pele é uma etapa crucial para o sucesso dessa biotécnica. Portanto, o objetivo do presente estudo, foi caracterizar o sistema tegumentar auricular periférico de catetos, visando aprimorar a conservação tecidual. Para tanto, fragmentos auriculares de oito animais foram avaliados quanto às camadas teciduais, aos componentes, à atividade proliferativa e à viabilidade metabólica, usando-se as colorações hematoxilina-eosina e tricrômico de Gomori, quantificação de AgNORs e microscopia eletrônica de transmissão. Assim, tamanhos de 104,2µm e 222,6µm foram observados para epiderme e derme, com uma proporção volumétrica de 36,6% e 58,7%, respectivamente. Além disso, na epiderme, foram evidenciadas as camadas basal (22,5µm), intermediárias (53,5µm) e córnea (28,2µm), com valores médios de 65,3 células epidermais, 43,4 melanócitos e 14,8 halos perinucleares. Já a derme apresentou 127 fibroblastos, com 2,5 AgNORs/nucléolo. Adicionalmente, a atividade metabólica foi de 0,243. Em conclusão, o sistema tegumentar auricular periférico de catetos possui algumas marcantes variações em relação a outros mamíferos, quanto ao número de camadas e espessura da epiderme, quantidade de células epidermais, melanócitos e parâmetros proliferativos.

Conservation of somatic tissue derived from collared peccaries (Pecari tajacu Linnaeus, 1758) using direct or solid-surface vitrification techniques

Cryopreservation of somatic tissue can be applied in biodiversity conservation, especially for wild species as collared peccary. We aimed to evaluate the effect of vitrification techniques of ear tissue of collared peccary [direct vitrification in cryovials (DVC) or solid-surface vitrification (SSV)] on the layers of epidermis and dermis by conventional histology and cell ability during the in vitro culture. Thus, both the vitrification methods were able to maintain normal patterns of the epidermis as the cornea and granular layers, furthermore the intercellular space and dermal-epidermal junction of the spinous layer when compared to fresh control. Nevertheless, DVC and SSV percentage of normality decreased in the morphological integrity of cytoplasm (37.5 and 25.0%) of spinous layer, respectively, as compared to the fresh fragments (100%, p < 0.05). Moreover, other differences between the fresh control (100%) and DVC tissues were verified in the intra-epidermal cleavage of the spinous (37.5%) and basal (37.5%) layers. In general, DVC and SSV techniques were efficient for the recovery of the somatic cells according to most of the evaluated parameters for the in vitro culture (p > 0.05). In addition, only at time of 72 h (D3), in the growth curve, DVC fragments showed a reduced cell concentration than fresh control. In conclusion, SSV was found to be a more efficient method for vitrifying collared peccary skin tissue when compared to DVC. These results are relevant for the tissue cryopreservation from collared peccary and could also be useful for mammals with phylogenetic relationships.

In vitro culture of somatic cells derived from ear tissue of collared peccary (Pecari tajacu Linnaeus, 1758) in medium with different requirements

ABSTRACT: The maintenance of metabolic activities during the in vitro culture of somatic cells of wild animals, especially collared peccary (Pecari tajacu), is an interesting step in conservation of these cells for the use in nuclear transfer. In this context, it is necessary to optimize the culture conditions of somatic cells by the establishment of appropriate supplementation to the media. Therefore, this study aimed to analyze the composition of the culture means of somatic cell derived from ear tissue of collared peccaries, evaluating concentrations of fetal bovine serum (FBS; 10% vs. 20%) and epidermal growth factor (EGF; 5ng/mL vs. 10ng/mL). Tissues were submitted to primary culture and subcultures for 40 days and cells were analyzed for morphology, adhesion, subconfluence, and proliferative activity to develop the growth curve and to determine the population doubling time (PDT), viability, and functional/metabolic activity. No difference was observed between the concentrations of FBS for several parameters, except for viability [FBS10: 85.6% vs. FBS20: 98.2%], PDT [FBS10: 155.4h vs. 77.2h], and functional/metabolic assay [FBS10: 0.57-0.55 vs. FBS20: 0.82-0.99 (D5-D7)]. For the EGF in culture, no difference was observed in the evaluated parameters. In all experiments, the growth curves were typical S-shape and the cells passed through a lag, logarithmic, and plateau phase. In conclusion, 20% FBS is suitable for the recovery of somatic cells; nevertheless, EGF does not improve the quality of growing these cells. To our knowledge, this is the first study culturing somatic cells of collared peccaries.

A Road Map for 21st Century Genetic Restoration: Gene Pool Enrichment of the Black-Footed Ferret

Interspecies somatic cell nuclear transfer (iSCNT) could benefit recovery programs of critically endangered species but must be weighed with the risks of failure. To weigh the risks and benefits, a decision-making process that evaluates progress is needed. Experiments that evaluate the efficiency and efficacy of blastocyst, fetal, and post-parturition development are necessary to determine the success or failure or species-specific iSCNT programs. Here, we use the black-footed ferret (Mustela nigripes) as a case study for evaluating this emerging biomedical technology as a tool for genetic restoration. The black-footed ferret has depleted genetic variation yet genome resource banks contain genetic material of individuals not currently represented in the extant lineage. Thus, genetic restoration of the species is in theory possible and could help reduce the persistent erosion of genetic diversity from drift. Extensive genetic, genomic, and reproductive science tools have previously been developed in black-footed ferrets and would aid in the process of developing an iSCNT protocol for this species. Nonetheless, developing reproductive cloning will require years of experiments and a coordinated effort among recovery partners. The information gained from a well-planned research effort with the goal of genetic restoration via reproductive cloning could establish a 21st century model for evaluating and implementing conservation breeding that would be applicable to other genetically impoverished species.

DogMATIC--A Remote Biospecimen Collection Kit for Biobanking

Canine tumors are valuable comparative oncology models. This research was designed to create a sustainable biobank of canine mammary tumors for breast cancer research. The aim was to provide a well-characterized sample cohort for specimen sharing, data mining, and long-term research aims. Canine mammary tumors are most frequently managed at a local veterinary clinic or hospital. We adopted a biobank framework based on a large number of participating veterinary hospitals and clinics acting as collection centers that were serviced by a centralized storage facility. Recruitment was targeted at rural veterinary clinics. A tailored, stable collection kit (DogMATIC) was designed that was used by veterinarians in remote or rural locations to collect both fresh and fixed tissue for submission to the biobank. To validate this methodology the kit design, collection rate, and sample quality were analyzed. The Australian Veterinary Cancer Biobank was established as a network of 47 veterinary clinics and three veterinary pathology laboratories spanning over 200,000 km(2). In the first 12 months, 30 canine mammary tumor cases were submitted via the DogMATIC kit. Pure intact RNA was isolated in over 80% of samples with an average yield of 14.49 μg. A large network biobank, utilizing off-site collection with the DogMATIC kit, was successfully coordinated. The creation of the Australian Veterinary Cancer Biobank has established a long-term, sustainable, comparative oncology research resource in Australia. There are broader implications for biobanking with this very different form of collection and banking.

Effect of testicle postmortem storage on goat frozen-thawed epididymal sperm quality as a tool to improve genebanking in local breeds

The interest to develop assisted reproductive technologies and cryobanking for farm animal genetic resource conservation has recently increased. However, cryopreservation for ex-situ management of genetic diversity sometimes is not routinely feasible, owing to the lack of facilities (AI centres, laboratories) and expertise near the local breed farming area. In these cases, epididymal sperm obtained from slaughtered or castrated animals, associated with the possibility of managing rather long periods between animal death, sperm recovery and freezing, would increase the opportunities to create semen storages. This investigation addresses the pre-freeze/post-thaw quality of goat epididymal sperm as a function of testicle storage temperature (environment or +5°C) and time elapsed between animal's death and sperm recovery (0, 24, 48, 72 h) to establish the optimal protocols for the recovery and cryopreservation of epididymal sperm in this species. Testicles of 50 mature bucks collected at the abattoir were divided in two groups: half of the testicles (n=50) were transported to the laboratory at environment temperature (E), whereas the remaining half (n=50) at a refrigeration temperature (R) of +5°C. In the two groups (E) and (R), one testicle from each pair was processed after slaughter forming the time 0 groups (0E and 0R). The contralateral testicle was processed after 24, 48 or 72 h of storage, at the corresponding temperature. Sperm motility and kinetic parameters, viability and morphology were assessed in pre-freeze and post-thaw samples. Until 48 h postmortem, both E and R temperatures are able to maintain good pre-freeze epididymal sperm quality. After 48 h postmortem, R temperature is fundamental to reduce epididymal sperm quality decay in pre-freeze samples. Moreover, testicle refrigeration also has a positive impact on post-thaw samples, allowing a lower decline through time considering total motility, kinetics parameters, sperm viability and sperm abnormalities. Therefore, when sperm cryopreservation is not immediately practicable, goat testicles should be transported and stored at 5°C up to a maximum of 48 h postmortem to ensure an acceptable sperm quality.

The effects of superoxide dismutase addition to the transport medium on cumulus-oocyte complex apoptosis and IVF outcome in cats (Felis catus)

The aim of the present study was to examine the effects of superoxide dismutase (SOD) addition to the ovary transport medium (4°C, 3-72 h) on ovarian cell viability and apoptosis and in vitro embryo production (IVEP) in domestic cats. The ovaries collected from 76 mixed-breed domestic queens were randomly assigned to the control or SOD-treated groups and incubated for 3, 24, 48 or 72 h. The ovaries were then subjected to the following: (1) fixed in formalin to assess the incidence of apoptosis (fragmented DNA in situ detection kit), (2) stored at -196°C in liquid nitrogen to evaluate the expression of the pro-apoptotic Bax gene and the anti-apoptotic Bcl-2 gene (RT-PCR), and (3) used to obtain the cumulus-oocyte complexes (COCs) in order to test the cell viability (carboxyfluorescein or trypan blue staining) and IVEP. The incidence of apoptosis appeared to be higher in the control compared with the SOD-treated ovaries. The ovarian expression of Bax was lower and the Bcl-2 expression was higher in the SOD-treated group compared with the control group. The presence of SOD in the transport medium increased the viability of COCs and IVEP compared with the control medium. In summary, the supplementation of the ovary transport medium with SOD reduced cellular apoptosis and enhanced COC survival and IVEP in domestic cats.

The value of frozen cartilage tissues without cryoprotection for genetic conservation

Animal tissues frozen without cryoprotection are thought to be inappropriate for use as a donor for somatic cell nuclear transfer (SCNT) studies. Cells in tissues that have been frozen without a cryoprotectant are commonly thought to be dead or to have lost genomic integrity. However, in this study we show that the frozen auricular cartilage tissues of anatolian buffalo contain a considerable number of viable healthy cells. The cells in auricular cartilage tissues are resistant to cryo-injury at -80°C. Primary cell cultures were established from defrosted ear tissues which were frozen without cryoprotectant. The growth and functional characteristics of primary cell cultures are characterized according to cell growth curve, cell cycle analysis, karyotype and GAG synthesis. The results indicate that frozen cartilage tissues could be valuable materials for the conservation of species and SCNT technology.

Gene sets for utilization of primary and secondary nutrition supplies in the distal gut of endangered Iberian lynx

Recent studies have indicated the existence of an extensive trans-genomic trans-mural co-metabolism between gut microbes and animal hosts that is diet-, host phylogeny- and provenance-influenced. Here, we analyzed the biodiversity at the level of small subunit rRNA gene sequence and the metabolic composition of 18 Mbp of consensus metagenome sequences and activity characteristics of bacterial intra-cellular extracts, in wild Iberian lynx (Lynx pardinus) fecal samples. Bacterial signatures (14.43% of all of the Firmicutes reads and 6.36% of total reads) related to the uncultured anaerobic commensals Anaeroplasma spp., which are typically found in ovine and bovine rumen, were first identified. The lynx gut was further characterized by an over-representation of ‘presumptive’ aquaporin aqpZ genes and genes encoding ‘active’ lysosomal-like digestive enzymes that are possibly needed to acquire glycerol, sugars and amino acids from glycoproteins, glyco(amino)lipids, glyco(amino)glycans and nucleoside diphosphate sugars. Lynx gut was highly enriched (28% of the total glycosidases) in genes encoding α-amylase and related enzymes, although it exhibited low rate of enzymatic activity indicative of starch degradation. The preponderance of β-xylosidase activity in protein extracts further suggests lynx gut microbes being most active for the metabolism of β-xylose containing plant N-glycans, although β-xylosidases sequences constituted only 1.5% of total glycosidases. These collective and unique bacterial, genetic and enzymatic activity signatures suggest that the wild lynx gut microbiota not only harbors gene sets underpinning sugar uptake from primary animal tissues (with the monotypic dietary profile of the wild lynx consisting of 80–100% wild rabbits) but also for the hydrolysis of prey-derived plant biomass. Although, the present investigation corresponds to a single sample and some of the statements should be considered qualitative, the data most likely suggests a tighter, more coordinated and complex evolutionary and nutritional ecology scenario of carnivore gut microbial communities than has been previously assumed.

Human tissue biobanks: the balance between consent and the common good

Biobanks are currently archiving human materials for medical research at a hitherto unprecedented rate. These valuable resources will be essential for developing ‘personalized’ medicines and for a better understanding of disease susceptibilities. However, for such scientific advances to benefit everyone, it is crucial that biobanks recruit donations from all sections of the community. Unfortunately, other initiatives, such as transplant programmes, have clearly demonstrated that ethnic minorities are under-represented. Here we suggest that this issue deserves serious consideration to avoid biobanks evolving into ethnically biased archives which unwittingly promote race-specific research. Specifically, this necessitates research ethics committees engaging in a re-assessment of the relative merits of individual personal sovereignty and the common good.

Using cell banks as a tool in conservation programmes of native domestic breeds: the production of the first cloned Anatolian Grey cattle

The aim of this study was to clone native Anatolian Grey cattle by using different donor cell types, such as fibroblast, cartilage and granulosa cells cryopreserved in a gene bank and oocytes aspirated from ovaries of Holstein cows as the recipient cytoplasm source. One male calf from fibroblast, three female calves from granulosa cells and one female calf from cartilage cells were born healthy and at normal birthweights. No calves were lost after birth. The results demonstrated that the cloned calves had the same microsatellite alleles at 11 loci as their nuclear donors. However, the mtDNAs of the five Anatolian Grey cloned calves had different haplotypes from their donor cells and mtDNA heteroplasmy could not be detected in any of the clones. The birth of healthy clones suggests that the haplotype difference between the cell and oocyte donor did not affect the pre- or post-implantation development of the bovine nuclear transfer derived embryos in our study. The results showed that well established nuclear transfer protocols could be useful in conserving endangered species. In conclusion, somatic cell banking can be suggested as a tool in conservation programmes of animal genetic resources.