Advances in Anatomy Embryology and Cell Biology最新文献

It is well known that plant cells do not contain typical centrosomes and the question has been asked how plant cells undergo mitosis and cell division in the absence of mechanisms that are well known for eukaryotic animal cells. Several papers are now available to address this question.

The centrosome field has seen enormous progress during the past few decades which spans the large areas of cell biology with new information on cell cycle controls and cellular health; immunology with centrosomes being essential for the formation of the immunological synapse; neurobiology with new insights into centrosome dysfunctions leading to disorders and disease; stem cell biology with fate-determining distribution of centrosomal material during asymmetric cell division; cancer biology with huge insights into the role of centrosomes in disease initiation, progression, and manifestation; reproductive biology with essential centrosome functions in oocytes, during fertilization and embryo development in which centrosome dysfunctions can be related back to abnormal centrosomal material in the meiotic spindle of oocytes; and several others that will be highlighted in the specific chapters of this book.

One of the most interesting aspects of host cell-viral interactions is how the pathogen exploits the host cell cytoskeleton and centrosomes for survival in the host cell.

Stem cells are important to sustain tissue growth during development, to repair damaged tissue after injury, and to maintain homeostasis during adulthood. Precisely programmed stem cell renewal and differentiation is critical, as failure in balance can lead to tumorigenesis as a result of over-proliferation or to degeneration as a result of decline in stem cell functions (reviewed in Roth et al (2012); Chen et al (2021).

In the vertebrate tree of life, viviparity or live birth has independently evolved many times, resulting in a rich diversity of reproductive strategies. Viviparity is believed to be a mode of reproduction that evolved from the ancestral condition of oviparity or egg laying, where most of the fetal development occurs outside the body. Today, there is not a simple model of parity transition to explain this species-specific divergence in modes of reproduction. Most evidence points to a gradual series of evolutionary adaptations that account for this phenomenon of reproduction, elegantly displayed by various viviparous squamates that exhibit placentae formed by the appositions of maternal and embryonic tissues, which share significant homology with the tissues that form the placenta in therian mammals. In an era where the genomes of many vertebrate species are becoming available, studies are now exploring the molecular basis of this transition from oviparity to viviparity, and in some rare instances its possible reversibility, such as the Australian three-toed skink (Saiphos equalis). In contrast to the parity diversity in squamates, mammals are viviparous with the notable exception of the egg-laying monotremes. Advancing computational tools coupled with increasing genome availability across species that utilize different reproductive strategies promise to reveal the molecular underpinnings of the ancestral transition of oviparity to viviparity. As a result, the dramatic changes in reproductive physiology and anatomy that accompany these parity changes can be reinterpreted. This chapter will briefly explore the vertebrate modes of reproduction using a phylogenetic framework and where possible highlight the role of potential candidate genes that may help explain the polygenic origins of live birth.

Chapter 8 was inadvertently published with errors and the following corrections were updated.

Pregnancy in pigs includes the events of conceptus (embryo/fetus and placental membranes) elongation, implantation, and placentation. Placentation in pigs is defined microscopically as epitheliochorial and macroscopically as diffuse. In general, placentation can be defined as the juxtapositioning of the endometrial/uterine microvasculature to the chorioallantoic/placental microvasculature to facilitate the transport of nutrients from the mother to the fetus to support fetal development and growth. Establishment of epitheliochorial placentation in the pig is achieved by: (1) the secretions of uterine glands prior to conceptus attachment to the uterus; (2) the development of extensive folding of the uterine-placental interface to maximize the surface area for movement of nutrients across this surface; (3) increased angiogenesis of the vasculature that delivers both uterine and placental blood and, with it, nutrients to this interface; (4) the minimization of connective tissue that lies between these blood vessels and the uterine and placental epithelia; (5) interdigitation of microvilli between the uterine and placental epithelia; and (6) the secretions of the uterine glands, called histotroph, that accumulate in areolae for transport though the placenta to the fetus. Placentation in pigs is not achieved by invasive growth of the placenta into the uterus. In this chapter, we summarize current knowledge about the major events that occur during the early stages of implantation and placentation in the pig. We will focus on the microanatomy of porcine placentation that builds off the excellent histological work of Amoroso and others and provide a brief review of some of the key physiological, cellular, and molecular events that accompany the development of "implantation" in pigs.