Showing papers in "Annual Review of Animal Biosciences in 2018"

Bat Biology, Genomes, and the Bat1K Project: To Generate Chromosome-Level Genomes for All Living Bat Species

Abstract: Bats are unique among mammals, possessing some of the rarest mammalian adaptations, including true self-powered flight, laryngeal echolocation, exceptional longevity, unique immunity, contracted genomes, and vocal learning. They provide key ecosystem services, pollinating tropical plants, dispersing seeds, and controlling insect pest populations, thus driving healthy ecosystems. They account for more than 20% of all living mammalian diversity, and their crown-group evolutionary history dates back to the Eocene. Despite their great numbers and diversity, many species are threatened and endangered. Here we announce Bat1K, an initiative to sequence the genomes of all living bat species (n∼1,300) to chromosome-level assembly. The Bat1K genome consortium unites bat biologists (>148 members as of writing), computational scientists, conservation organizations, genome technologists, and any interested individuals committed to a better understanding of the genetic and evolutionary mechanisms that underlie the unique adaptations of bats. Our aim is to catalog the unique genetic diversity present in all living bats to better understand the molecular basis of their unique adaptations; uncover their evolutionary history; link genotype with phenotype; and ultimately better understand, promote, and conserve bats. Here we review the unique adaptations of bats and highlight how chromosome-level genome assemblies can uncover the molecular basis of these traits. We present a novel sequencing and assembly strategy and review the striking societal and scientific benefits that will result from the Bat1K initiative.

The Divergent Genomes of Teleosts

Abstract: Boasting nearly 30,000 species, teleosts account for half of all extant vertebrates and approximately 98% of all ray-finned fish species (Actinopterygii). Teleosts are also the largest and most diverse group of vertebrates, exhibiting an astonishing level of morphological, physiological, and behavioral diversity. Previous studies had indicated that the teleost lineage has experienced an additional whole-genome duplication event. Recent comparative genomic analyses of teleosts and other bony vertebrates using spotted gar (a nonteleost ray-finned fish) and elephant shark (a cartilaginous fish) as outgroups have revealed several divergent features of teleost genomes. These include an accelerated evolutionary rate of protein-coding and nucleotide sequences, a higher rate of intron turnover, loss of many potential cis-regulatory elements and shorter conserved syntenic blocks. A combination of these divergent genomic features might have contributed to the evolution of the amazing phenotypic diversity and morphological innovations of teleosts.

Detection of Emerging Zoonotic Pathogens: An Integrated One Health Approach

Abstract: The emergence of novel zoonotic pathogens is one of the greatest challenges to global health security. The advent of increasingly sophisticated diagnostics tools has revolutionized our capacity to detect and respond to these health threats more rapidly than ever before. Yet, no matter how sophisticated these tools become, the initial identification of emerging infectious diseases begins at the local community level. It is here that the initial human or animal case resides, and it is here that early pathogen detection would have maximum benefit. Unfortunately, many areas at highest risk of zoonotic disease emergence lack sufficient infrastructure capacity to support robust laboratory diagnostic systems. Multiple factors are essential for pathogen detection networks, including an understanding of the complex sociological and ecological factors influencing disease transmission risk, community engagement, surveillance along high-risk human-animal interfaces, and a skilled laboratory workforce. Here we discuss factors relevant to the emerging disease paradigm, recent technical advances in diagnostic methods, and strategies for comprehensive and sustainable approaches to rapid zoonotic disease detection.

Measuring Male-to-Male Differences in Fertility or Effects of Semen Treatments.

Abstract: Fertility is a convenient but meaningless term unless the outcome measure is stipulated and accounts for dependence of male fertility on the female population. We describe outcome measures and detail the impacts of the physiological status of each female and her external environment, as well as management imposed by humans. We explain the dominant role of the female reproductive tract as a series of hurdles for sperm seeking an ovum. Each spermatozoon in an ejaculate is unique, although usually most are morphologically similar. Semen seemingly contains three subpopulations of sperm, based on fate within a female and role in hampering the success of the ultimate winning spermatozoon; we define these subpopulations. The numerical size of each subpopulation placed into a female determines the shape of the dose-response curve leading to possible live young. Heterospermic artificial insemination provides far greater sensitivity to detect differences, partly because the female environment is identical for each comparison.

Viable Cell Culture Banking for Biodiversity Characterization and Conservation.

Abstract: Because living cells can be saved for indefinite periods, unprecedented opportunities for characterizing, cataloging, and conserving biological diversity have emerged as advanced cellular and genetic technologies portend new options for preventing species extinction. Crucial to realizing the potential impacts of stem cells and assisted reproductive technologies on biodiversity conservation is the cryobanking of viable cell cultures from diverse species, especially those identified as vulnerable to extinction in the near future. The advent of in vitro cell culture and cryobanking is reviewed here in the context of biodiversity collections of viable cell cultures that represent the progress and limitations of current efforts. The prospects for incorporating collections of frozen viable cell cultures into efforts to characterize the genetic changes that have produced the diversity of species on Earth and contribute to new initiatives in conservation argue strongly for a global network of facilities for establishing and cryobanking collections of viable cells.

Catfish Biology and Farming

Abstract: This article summarizes the biology and culture of ictalurid catfish, an important commercial, aquaculture, and sport fish family in the United States The history of the propagation as well as spawning of common catfish species in this family is reviewed, with special emphasis on channel catfish and its hybridization with blue catfish The importance of the channel catfish female×blue catfish male hybrid, including current and future methods of hybrid catfish production, and the potential role it plays in the recovery of the US catfish industry are discussed Recent advances in catfish culture elements, including environment, management, nutrition, feeding, disease control, culture systems, genetic improvement programs, transgenics, and the application of genome-based approaches in catfish production and welfare, are reviewed The current status, needs, and future projections are discussed, as well as genetically modified organism developments that are changing the future

Impact of Micronutrients on the Immune Response of Animals

Abstract: Vitamins and minerals (micronutrients) play an important role in regulating and shaping an immune response. Deficiencies generally result in inadequate or dysregulated cellular activity and cytokine expression, thereby affecting the immune response. Decreased levels of natural killer, granulocyte, and phagocytic cell activity and T and B cell proliferation and trafficking are associated with inadequate levels of micronutrients, as well as increased susceptibility to various adverse health conditions, including inflammatory disorders, infection, and altered vaccine efficacy. In addition, most studies of micronutrient modulation of immune responses have been done in rodents and humans, thus limiting application to the health and well-being of livestock and companion animals. This exploratory review elucidates the role of vitamins and minerals on immune function and inflammatory responses in animals (pigs, dogs, cats, horses, goats, sheep, and cattle), with reference to rodents and humans.

Metabolic and Endocrine Role of Adipose Tissue During Lactation.

Abstract: The adipose tissue serves an essential role for survival and reproduction in mammals, especially females. It serves primarily as an energy storage organ and is directly linked to the reproductive success of mammals. In wild animals, adipose tissue function is linked to seasonality of the food supply to support fetal growth and milk production. Adipose tissue depots in ruminants and non-ruminants can secrete many signal molecules (adipokines) that act as hormones and as pro- and anti-inflammatory cytokines. The visceral adipose tissue especially appears to be more endocrinologically active than other adipose depots. The endocrine function is important for the overall long-term regulation of energy metabolism and plays an important role in the adaptation to lactation in many mammalian species, including humans. Furthermore, endocrine signals from adipose tissue depots contribute to fertility modulation, immune function, and inflammatory response. Energy homeostasis is modulated by changes in feed intake, insulin sensitivity, and energy expenditure, processes that can be influenced by adipokines in the brain and in peripheral tissues.

Reproductive Impacts of Endocrine-Disrupting Chemicals on Wildlife Species: Implications for Conservation of Endangered Species.

Abstract: Wildlife have proven valuable to our understanding of the potential effects of endocrine-disrupting chemicals (EDCs) on human health by contributing considerably to our understanding of the mechanisms and consequences of EDC exposure. But the threats EDCs present to populations of wildlife species themselves are significant, particularly for endangered species whose existence is vulnerable to any reproductive perturbation. However, few studies address the threats EDCs pose to endangered species owing to challenges associated with their study. Here, we highlight those barriers and review the available literature concerning EDC effects on endangered species. Drawing from other investigations into nonthreatened wildlife species, we highlight opportunities for new approaches to advance our understanding and potentially mitigate the effects of EDCs on endangered species to enhance their fertility.

Biobanking Genetic Material for Agricultural Animal Species.

Abstract: Biobanking animal germplasm and tissues is a major component of conserving genetic resources Effectively constructing such gene banks requires an understanding and evaluation of genetic resources, the ability to conserve various tissues through cryopreservation, and a robust information technology infrastructure to allow managers and potential users to fully understand and make use of the collection Progress has been made internationally in developing national genetic resource collections As these collections have been developed, it has become apparent that gene banks can serve a multitude of roles, thereby serving short- and long-term needs of research communities and industry This article documents the development of gene banks and provides examples of how they have been used to date and the extent to which they have captured genetic diversity for future use

Development and Function of the Mucosal Immune System in the Upper Respiratory Tract of Neonatal Calves

Abstract: Respiratory infections remain the second most common cause of clinical disease and mortality in newborn calves, which has led to increased interest in using vaccines early in life to mitigate this risk. Intranasal vaccination of neonatal calves can be an effective strategy to circumvent vaccine interference by maternal antibody, but this raises questions regarding onset of immune competence in the upper respiratory tract (URT) following birth. Little is known, however, about the development and function of mucosa-associated lymphoid tissue (MALT) in the URT of newborn calves and what factors, including the commensal microbiome, contribute to this early development. We review the structure, development, and function of MALT in the bovine URT during the first six weeks of life and identify knowledge gaps regarding this early developmental time. This information is critical when designing vaccination programs for young calves, especially when targeting respiratory pathogens that may reside within the commensal microbiome.

Lessons from the Barn to the Operating Suite: A Comprehensive Review of Animal Models for Fetal Surgery.

Abstract: The International Fetal Medicine and Surgery Society was created in 1982 and proposed guidelines for fetal interventions that required demonstrations of the safety and feasibility of intended interventions in animal models prior to application in humans. Because of their short gestation and low cost, small animal models are useful in early investigation of fetal strategies. However, owing to the anatomic and physiologic differences between small animals and humans, repeated studies in large animal models are usually needed to facilitate translation to humans. Ovine (sheep) models have been used the most extensively to study the pathophysiology of congenital abnormalities and to develop techniques for fetal interventions. However, nonhuman primates have uterine and placental structures that most closely resemble those of humans. Thus, the nonhuman primate is the ideal model to develop surgical and anesthetic techniques that minimize obstetrical complications.

Nutrient-sensing biology in mammals and birds.

Abstract: Nutrient-sensing mechanisms have emerged as the fringe articulating nutritional needs with dietary choices. Carbohydrate, amino acid, fatty acid, mineral, and water-sensing receptors are highly conserved across mammals and birds, consisting of a repertoire of 22 genes known to date. In contrast, bitter receptors are highly divergent and have a high incidence of polymorphisms within and between mammals and birds and are involved in the adaptation of species to specific environments. In addition, the expression of nutrient-sensing genes outside the oral cavity seems to mediate the required decision-making dialogue between the gut and the brain by translating exogenous chemical stimuli into neuronal inputs, and vice versa, to translate the endogenous signals relevant to the nutritional status into specific appetites and the control of feed intake. The relevance of these sensors in nondigestive systems has uncovered fascinating potential as pharmacological targets relevant to respiratory and cardiovascular di...

Weird Animals, Sex, and Genome Evolution

Abstract: Making my career in Australia exposed me to the tyranny of distance, but it gave me opportunities to study our unique native fauna. Distantly related animal species present genetic variation that we can use to explore the most fundamental biological structures and processes. I have compared chromosomes and genomes of kangaroos and platypus, tiger snakes and emus, devils (Tasmanian) and dragons (lizards). I particularly love the challenges posed by sex chromosomes, which, apart from determining sex, provide stunning examples of epigenetic control and break all the evolutionary rules that we currently understand. Here I describe some of those amazing animals and the insights on genome structure, function, and evolution they have afforded us. I also describe my sometimes-random walk in science and the factors and people who influenced my direction. Being a woman in science is still not easy, and I hope others will find encouragement and empathy in my story.

Equine Intestinal Mucosal Pathobiology.

Abstract: The equine intestinal mucosa is intimately involved in maintaining homeostasis both on a systemic level by controlling extracellular fluid movement and at the local level to maintain barrier function. Horses are particularly susceptible to the clinical syndrome of colic, with the most severe cases involving strangulating obstruction that induces ischemia. Because of the mucosal vascular architecture, the mucosal epithelium is particularly susceptible to ischemic injury. The potential for reperfusion injury has been investigated and found to play a minimal role. However, inflammation does affect mucosal repair. Mechanisms of repair, including villus contraction, epithelial restitution, and tight junction closure, are critical to reforming the mucosal barrier. Nonsteroidal anti-inflammatory drugs have an impact on this repair, particularly at the level of the tight junctions. Completion of mucosal regeneration requires proliferation, which is now being actively studied in equine enteroids. All of these aspects of equine mucosal pathobiology are reviewed in depth.