bluuebunny/crossref_metadata_2025_split huggingface dataset:
Testosterone and Partner Compatibility: Evidence and Emerging Questions
Authors: Hirschenhauser Katharina 
Published: July 2012

AbstractIn socially monogamous species pair partners often form and maintain long‐term pair‐bonds. Relationships between pair partners are dynamic and driven by both cooperation and conflicts between the sexes. Successful reproduction depends on behavioural coordination and cooperation, which includes continuing mutual responsiveness between the pair partners, as well as conflicts, for example, over parental investment. Gonadal hormones, such as testosterone, centrally regulate reproduction and are potentially involved in the formation and maintenance of pair‐bonds. In greylag geese (Anser anser), a positive within‐pair testosterone co‐variation (TC) among pair partners has been observed at the seasonal level. Goose pairs with a higherTChave a higher reproductive output and long‐term success than pairs with lowerTC, but it is still not clear whetherTCis cause or consequence. In this article, I (i) summarize the evidence for hormonal partner compatibility in geese, (ii) ask whetherTCis restricted to monogamous and biparental systems and (iii) synthesize open questions or new aspects of information we may draw by studying hormonal partner compatibility. From longitudinal studies in geese, we know thatTCdecreases with pair‐bond duration. This indicates some form of ‘attritional effect’ over the years rather than an improved breeding performance with increasing familiarity between the partners (the ‘mate familiarity hypothesis’). Under certain circumstances, for example, during ageing, selection may not act in the same direction for males and females. Partner preference increased female androgen levels during laying and social instability may impinge on the pair'sTC. Data from other species show thatTCis not restricted to monogamous species, but presumably the link betweenTCand reproductive output may be primarily relevant in species with biparental care. This article surveys the major unanswered questions relating to hormonal partner compatibility and previews potential future work for addressing those open issues.
Exploiting Multimedia in Reproductive Science Education: Research Findings
Authors: Senger PL , Oki AC , Trevisan MS , McLean DJ 
Published: July 2012

ContentsEducation in reproductive science is operating from an outdated paradigm of teaching and learning. Traditionally, reproductive education follows the pattern where students read a textbook, listen to instructor presentations, re‐read the textbook and class notes and then complete a test. This paradigm is inefficient, costly and has not incorporated the potential that technology can offer with respect to increases in student learning. Further, teachers of reproductive science (and all of science for that matter) have little training in the use of documented methods of instructional design and cognitive psychology. Thus, most of us have learned to teach by repeating the approaches our mentors used (both good and bad). The technology now exists to explain complex topics using multimedia presentations in which digital animation and three‐dimensional anatomical reconstructions greatly reduce time required for delivery while at the same time improving student understanding. With funding from the Small Business Innovation Research program through the U.S. Department of Education, we have developed and tested a multimedia approach to teaching complex concepts in reproductive physiology. The results of five separate experiments involving 1058 university students and 122 patients in an OB/GYN clinic indicate that students and patients learned as much or more in less time when viewing the multimedia presentations when compared to traditional teaching methodologies.
Ethics, Politics and Protests: Using Contentious Issues in Reproductive Sciences as Educational Opportunities
Authors: Knight JW 
Published: July 2012

ContentsContentious issues and polarized viewpoints can be utilized in the classroom and beyond to create a reflective dialogue among students and citizens. This dialogue leads to both a greater understanding, as well as an enhanced appreciation of alternative viewpoints. Exploring and discussing the scientific, ethical, moral, political, legal and societal aspects of contentious issues of human reproduction provides ideal subject matter for developing critical thinking skills in the field of reproductive science.
Twenty Years of Embryonic Stem Cell Research in Farm Animals
Authors: Blomberg LA , Telugu BPVL 
Published: July 2012

ContentsNotable distinctions between an embryonic stem cell (ESC) and somatic cell are that an ESC can maintain an undifferentiated state indefinitely, self‐renew, and is pluripotent, meaning that the ESC can potentially generate cells representing all the three primordial germ layers and contribute to the terminally differentiated cells of a conceptus. These attributes make the ESC an ideal source for genome editing for both agricultural and biomedical applications. Although, ESC lines have been successfully established from rodents and primates, authentic ungulate stem cell lines on the contrary are still not available. Outstanding issues including but not limited to differences in pluripotency characteristics among the existing ESC lines, pre‐implantation embryo development, pluripotency pathways, and culture conditions plague our efforts to establish authentic ESC lines from farm animals. In this review, we highlight some of these issues and discuss how the recent derivation of induced pluripotent stem cells (iPSCs) might augur the establishment of robust authentic ESC lines from farm animals.
Pluripotency Network in Porcine Embryos and Derived Cell Lines
Authors: Brevini TAL , Pennarossa G , Maffei S , Gandolfi F 
Published: July 2012

ContentsHuge amounts of work have been dedicated to the establishment of embryonic stem cell lines from farm animal species since the successful isolation of embryonic stem cells from the mouse and from the human. However, no conclusive results have been obtained so far, and validated lines have yet to be established in domestic animals. Many limiting factors have been suggested and need to be studied further to isolate truly pluripotent cell lines from livestock. In this review, we will discuss the difficulties in deriving and maintaining embryonic stem cell lines from farm animal embryos and how can this lack of success be explained. We will summarize results obtained in our laboratory regarding derivation of pluripotent cells in the pigs. Problems related to the identification of standard methods for derivation, maintenance and characterization of cell lines will also be examined. We will focus our attention on the need for appropriate stemness‐related marker molecules that can be used to reliably investigate pluripotency in domestic species. Finally, we will review data presently available on functional key pluripotency‐maintaining pathways in farm animals.
Advancing Pig Cloning Technologies Towards Application in Regenerative Medicine
Authors: Nagashima H , Matsunari H , Nakano K , Watanabe M , Umeyama K , Nagaya M 
Published: July 2012

ContentsRegenerative medicine is expected to make a significant contribution by development of novel therapeutic treatments for intractable diseases and for improving the quality of life of patients. Many advances in regenerative medicine, including basic and translational research, have been developed and tested in experimental animals; pigs have played an important role in various aspects of this work. The value of pigs as a model species is being enhanced by the generation of specially designed animals through cloning and genetic modifications, enabling more sophisticated research to be performed and thus accelerating the clinical application of regenerative medicine. This article reviews the significant aspects of the creation and application of cloned and genetically modified pigs in regenerative medicine research and considers the possible future directions of the technology. We also discuss the importance of reproductive biology as an interface between basic science and clinical medicine.
The Role of Progesterone in Oocyte Acquisition of Developmental Competence
Authors: Fair T , Lonergan P 
Published: July 2012

ContentsIt is generally accepted that progesterone (P4) is a key regulator of reproductive function in mammals. In cattle, the primary focus of P4’s actions has been uterine receptivity and maintenance of pregnancy. Studies in mammalian laboratory species and ovarian derived cell lines also highlight their role in ovarian function. Extensive research in non‐mammalian species has elucidated a critical role for P4 and both its nuclear and membrane‐bound receptors in oocyte maturation and ovulation. Until recently, such a role in mammalian oocytes has been disputed. However, as oestrous synchronization regimes are constantly tweaked and revised to maximize pregnancy rates to artificial insemination in cattle, the importance of P4 priming of the dominant ingfollicle is once again tak centre stage. Sequencing of the bovine genome and the development of multiple transcriptomic data mining tools have facilitated an explosion in global transcriptome profiling of immature and matured oocytes and their surrounding cumulus cells. Many of the differentially regulated genes and their associated preferentially populated pathways appear to be P4 regulated in other tissues. Therefore, attention is once again turning to a potential role for P4 in ovulatory follicle development and oocyte maturation in cattle. The current review summarizes the most recent findings in these areas.
What Sperm Can Teach us About Energy Production
Authors: Mukai C , Travis AJ 
Published: July 2012

ContentsMammalian sperm have evolved under strict selection pressures that have resulted in a highly polarized and efficient design. A critical component of that design is the compartmentalization of specific metabolic pathways to specific regions of the cell. Although the restricted localization of mitochondria to the midpiece is the best known example of this design, the organization of the enzymes of glycolysis along the fibrous sheath is the primary focus of this review. Evolution of variants of these metabolic enzymes has allowed them to function when tethered, enabling localized energy production that is essential for sperm motility. We close by exploring how this design might be mimicked to provide an energy‐producing platform technology for applications in nanobiotechnology.
Directional Freezing of Reproductive Cells and Organs
Authors: Arav A , Natan D 
Published: July 2012

ContentsDirectional freezing is based on a simple thermodynamic principle where ice crystals are precisely controlled through the sample by regulating the velocity of the sample movement through the predetermined temperature gradient. Directional freezing permits a precise and uniform cooling rate in both small and large volume samples. Directional freezing was used for slow and rapid freezing, as well as for vitrification of oocytes and embryos using the minimum drop size technique. Sperm samples from a wide range of domestic and wild animals were successfully cryopreserved using the directional freezing method. The method enabled, for the first time, successful freezing of a whole ovary and freeze‐drying of mammalian cells followed by thawing and transplantation and rehydration, respectively.
Controlled Stress Improves Oocyte Performance – Cell Preconditioning in Assisted Reproduction
Authors: Pribenszky C , Lin L , Du Y , Losonczi E , Dinnyes A , Vajta G 
Published: July 2012

ContentsA recently emerged concept utilizing a controlled environmental impact as a treatment for cells and tissues aims to improve neither the in vitro conditions nor the procedures, but the cell itself. Hydrostatic pressure stress emerged as the most controllable and most effective stressor, proving the principle that controlled stress improves cell performance in in vitro procedures, whereas further studies using different stressors (osmotic, oxidative or mechanic stresses) supported the principle. The present summary reviews studies of various stress treatments to treat oocytes of three species (murine, porcine, human) before vitrification, in vitro maturation, enucleation and somatic cell nuclear transfer. Eventually, cleavage and blastocyst rates and – in cases when hydrostatic pressure was used – blastocyst cell number and birth rates as well were significantly improved compared to untreated controls.
Progress in Development of Immunocontraceptive Vaccines for Permanent Non‐surgical Sterilization of Cats and Dogs
Authors: Munks MW 
Published: July 2012

ContentsEach year, millions of cats and dogs are euthanized worldwide. There are insufficient resources to control shelter animals in developed countries, as well as feral cat and wild dog population levels, with current surgical sterilization techniques. Thus, population control of these animals will likely depend on the development of new non‐surgical methods for cat and dog sterilization. One promising area of research is the development of contraceptive vaccines, or immunocontraceptives. In this article, previous approaches aimed at developing contraceptive vaccines will be reviewed, with a focus on those most related to sterilization of cats and dogs. There are a number of steps in reproduction that have been, or could be, targeted by the immune system, and the advantages and obstacles for inducing immunity to each of these will be discussed. Our current understanding of how these vaccines cause sterility, and our current ability to dissect these mechanisms in cats and dogs, also will be discussed.
Targeted Gene Silencing to Induce Permanent Sterility
Authors: Dissen GA , Lomniczi A , Boudreau RL , Chen YH , Davidson BL , Ojeda SR 
Published: July 2012

ContentsA non‐surgical method to induce sterility would be a useful tool to control feral populations of animals. Our laboratories have experience with approaches aimed at targeting brain cells in vivo with vehicles that deliver a payload of either inhibitory RNAs or genes intended to correct cellular dysfunction. A combination/modification of these methods may provide a useful framework for the design of approaches that can be used to sterilize cats and dogs. For this approach to succeed, it has to meet several conditions: it needs to target a gene essential for fertility. It must involve a method that can selectively silence the gene of interest. It also needs to deliver the silencing agent via a minimally invasive method. Finally, the silencing effect needs to be sustained for many years, so that expansion of the targeted population can be effectively prevented. In this article, we discuss this subject and provide a succinct account of our previous experience with: (i) molecular reagents able to disrupt reproductive cyclicity when delivered to regions of the brain involved in the control of reproduction and (ii) molecular reagents able to ameliorate neuronal disease when delivered systemically using a novel approach of gene therapy.
Genetic Selection and Conservation of Genetic Diversity*
Authors: Blackburn HD 
Published: July 2012

ContentsFor 100s of years, livestock producers have employed various types of selection to alter livestock populations. Current selection strategies are little different, except our technologies for selection have become more powerful. Genetic resources at the breed level have been in and out of favour over time. These resources are the raw materials used to manipulate populations, and therefore, they are critical to the past and future success of the livestock sector. With increasing ability to rapidly change genetic composition of livestock populations, the conservation of these genetic resources becomes more critical. Globally, awareness of the need to steward genetic resources has increased. A growing number of countries have embarked on large scale conservation efforts by usingin situ,ex situ(gene banking), or both approaches. Gene banking efforts have substantially increased and data suggest that gene banks are successfully capturing genetic diversity for research or industry use. It is also noteworthy that both industry and the research community are utilizing gene bank holdings. As pressures grow to meet consumer demands and potential changes in production systems, the linkage between selection goals and genetic conservation will increase as a mechanism to facilitate continued livestock sector development.
How Developments in Cryobiology, Reproductive Technologies and Conservation Genomics Could Shape Gene Banking Strategies for (Farm) Animals
Authors: Woelders H , Windig J , Hiemstra SJ 
Published: July 2012

ContentsMany local breeds are currently at risk because of replacement by a limited number of specialized commercial breeds. Concurrently, for many breeds, allelic diversity within breeds declines because of inbreeding. Gene banking of germplasm may serve to secure the breeds and the alleles for any future use, for instance to recover a lost breed, to address new breeding goals, to support breeding schemes in small populations to minimize inbreeding, and for conservation genetics and genomics research. Developments in cryobiology and reproductive technology have generated several possibilities for preserving germplasm in farm animals. Furthermore, in some mammalian and bird species, gene banking of material is difficult or impossible, requiring development of new alternative methods or improvement of existing methods. Depending on the species, there are interesting possibilities or research developments in the use of epididymal spermatozoa, oocytes and embryos, ovarian and testicular tissue, primordial germ cells, and somatic cells for the conservation of genetic diversity in farm‐ and other animal species. Rapid developments in genomics research also provide new opportunities to optimize conservation and sampling strategies and to characterize genome‐wide genetic variation. With regard to gene banks for farm animals, collaboration between European countries is being developed through a number of organizations, aimed at sharing knowledge and expertise between national programmes. It would be useful to explore further collaboration between countries, within the framework of a European gene banking strategy that should minimize costs of conservation and maximize opportunities for exploitation and sustainable use of genetic diversity.
Life or Death Decisions in the Corpus Luteum
Authors: Pate JL , Johnson‐Larson CJ , Ottobre JS 
Published: July 2012

ContentsThe corpus luteum (CL) is an ephemeral endocrine organ. During its lifespan, it undergoes a period of extremely rapid growth that involves hypertrophy, proliferation and differentiation of the steroidogenic cells, as well as extensive angiogenesis. The growth phase is followed by a period in which remodelling of the tissue ceases, but it engages in unparalleled production of steroids, resulting in extraordinarily high metabolic activity within the tissue. It is during this stage that a critical juncture occurs. In the non‐fertile cycle, uterine release of prostaglandin (PG)F2α initiates a cascade of events that result in rapid loss of steroidogenesis and destruction of the luteal tissue. Alternatively, if a viable embryo is present, signals are produced that result in rescue of the CL. This review article summarizes the major concepts related to the fate of the CL, with particular focus on recent insights into the mechanisms associated with the ability of PGF2α to bring about complete luteolysis. It has become clear that the achievement of luteolysis depends on repeated exposure to PGF2α and involves coordinated actions of heterogeneous cell types within the CL. Together, these components of the process bring about not only the loss in progesterone production, but also the rapid demise of the structure itself.
Reproduction in Farm Animals in an Era of Rapid Genetic Change: Will Genetic Change Outpace Our Knowledge of Physiology?
Authors: Foxcroft GR 
Published: July 2012

ContentsCompared with other domestic species, genetic nucleus selection has gradually increased both prolificacy and productivity of the breeding sow and the post‐natal growth performance of commercial progeny. However, increasing variation in litter birth weight and foetal development may be indirect consequences of interactions among multiple genes controlling prolificacy and prenatal development. Phenotypic plasticity in the litter phenotype also results from effects of sow metabolic state on the developing embryo. New genomic tools may provide the opportunity to better balance the selection of genes controlling the component traits affecting the size and quality of litters born, particularly in multiparous sows.
Environmental Pollutants and Diseases of Sexual Development in Humans and Wildlife in South Africa: Harbingers of Impact on Overall Health?
Authors: (Riana) Bornman MS , Bouwman Hindrik 
Published: July 2012

ContentsThis study deals with disorders of sexual development in humans, wildlife and animals in an urban nature reserve (RNR) and a currently DDT‐sprayed malarial area. High levels of oestrogenic chemical residues in water, sediment and tissue; skewed sex ratios; reduced biodiversity; gonadal malformations in sharptooth catfish and freshwater snails; intersex in catfish; and impaired spermatogenesis in catfish and striped mouse are of serious concern in the RNR. Persistent eggshell thinning in African darter eggs, intersex in male Mozambican tilapia, follicular atresia in females and impaired spermatogenesis in males following laboratory exposure of parent fish to environmentally relevant DDT and DDE concentrations, and abnormalities in freshwater snails were found in the DDT‐sprayed area. Human studies related to DDT exposure indicated impaired semen quality, a weak association with sperm chromatin defects and higher risks for external urogenital birth defects in those who were born to mothers whose houses were sprayed and those who were homemakers (stay at home mother) instead of being employed. These findings indicate that diseases of sexual development occurred in both human and wildlife populations exposed to environmental endocrine disruptor chemicals in South Africa. The chemical mixtures, possibly related to disorders of sexual differentiation (DSD), were very different between the two. However, DSD occurred concurrently in the malarial area, possibly indicating that humans and wildlife shared exposures. Moreover, it emphasizes the importance of suspecting disease in the other when disease is found in either human or wildlife populations.
Epigenetic Mechanisms in the Actions of Endocrine‐disrupting Chemicals: Gonadal Effects and Role in Female Reproduction
Authors: Uzumcu M , Zama AM , Oruc E 
Published: July 2012

ContentsThere is a heightened interest and concern among scientists, clinicians and regulatory agencies as well as the general public, regarding the effects of environmental endocrine‐disrupting chemicals (EDCs). In this review, we identify the main epigenetic mechanisms and describe key ovarian processes that are vulnerable to the epigenetic actions of EDCs. We also provide an overview of the human epidemiological evidence documenting the detrimental effects of several common environmental EDCs on female reproduction. We then focus on experimental evidence demonstrating the epigenetic effects of these EDCs in the ovary and female reproductive system, with an emphasis on methoxychlor, an organochlorine pesticide. We conclude the review by describing several critical issues in studying epigenetic effects of EDCs in the ovary, including transgenerational epigenetic effects.