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Journal of Experimental Zoology. Part... Apr 2024Reptiles display considerable diversity in reproductive behavior, making them great models to study the neuroendocrine control of reproductive behavior. Many reptile... (Review)
Review
Reptiles display considerable diversity in reproductive behavior, making them great models to study the neuroendocrine control of reproductive behavior. Many reptile species are seasonally breeding, such that they become reproductively active during their breeding season and regress to a nonreproductive state during their nonbreeding season, with this transition often prompted by environmental cues. In this review, we will focus on summarizing the neural and neuroendocrine mechanisms controlling reproductive behavior. Three major areas of the brain are involved in reproductive behavior: the preoptic area (POA), amygdala, and ventromedial hypothalamus (VMH). The POA and VMH are sexually dimorphic areas, regulating behaviors in males and females respectively, and all three areas display seasonal plasticity. Lesions to these areas disrupt the onset and maintenance of reproductive behaviors, but the exact roles of these regions vary between sexes and species. Different hormones influence these regions to elicit seasonal transitions. Circulating testosterone (T) and estradiol (E2) peak during the breeding season and their influence on reproduction is well-documented across vertebrates. The conversion of T into E2 and 5α-dihydrotestosterone can also affect behavior. Melatonin and corticosterone have generally inhibitory effects on reproductive behavior, while serotonin and other neurohormones seem to stimulate it. In general, there is relatively little information on the neuroendocrine control of reproduction in reptiles compared to other vertebrate groups. This review highlights areas that should be considered for future areas of research.
Topics: Female; Male; Animals; Reptiles; Brain; Reproduction; Testosterone; Sexual Behavior, Animal
PubMed: 38247297
DOI: 10.1002/jez.2783 -
Cell Biology International Aug 2023Primordial germ cells (PGCs), are the source of gametes in vertebrates. There are similarities in the development of PGCs of reptiles with avian and mammalian species... (Review)
Review
Primordial germ cells (PGCs), are the source of gametes in vertebrates. There are similarities in the development of PGCs of reptiles with avian and mammalian species PGCs development. PGCs culture has been performed for avian and mammalian species but there is no report for reptilian PGCs culture. In vitro culture of PGCs is needed to produce transgenic animals, preservation of endangered animals and for studies on cell behaviour and research on fertility. Reptiles are traded as exotic pets and a source of food and they are valuable for their skin and they are useful as model for medical research. Transgenic reptile has been suggested to be useful for pet industry and medical research. In this research different aspects of PGCs development was compared in three main classes of vertebrates including mammalian, avian and reptilian species. It is proposed that a discussion on similarities between reptilian PGCs development with avian and mammalian species helps to find clues for studies of reptilian PGCs development details and finding an efficient protocol for in vitro culture of reptilian PG.
Topics: Germ Cells; Cell Culture Techniques; Endangered Species; Reptiles; Cryopreservation; Animals, Genetically Modified; Gene Expression Regulation, Developmental; Epigenesis, Genetic; Animals
PubMed: 37178380
DOI: 10.1002/cbin.12033 -
Nature Ecology & Evolution May 2024
Topics: Animals; Dinosaurs; Fossils
PubMed: 38741008
DOI: 10.1038/s41559-024-02395-8 -
Current Biology : CB Jul 2023The histology of bone can be preserved virtually unaltered for hundreds of millions of years in fossils from all environments and all vertebrate taxa, giving rise to the...
The histology of bone can be preserved virtually unaltered for hundreds of millions of years in fossils from all environments and all vertebrate taxa, giving rise to the flourishing field of paleohistology. The shafts of long bones are formed by the apposition of periosteal bone tissue, similar to the growth of wood, and preserve, an often cyclical, record of the growth of the individual and events in its life history. One such event is sexual maturation or puberty, during which hormonal changes transform the juvenile into a sexually mature adult. Puberty has been well studied in humans and some other living vertebrates. Here, we describe puberty in Keichousaurus, a small sexually dimorphic and live-bearing marine reptile from Middle Triassic rocks of SW China, about 240 million years old. Using a combination of bone histology and morphology, we detected puberty as one of the four life stages (the others being fetus, juvenile, and adult). Adult Keichousaurus males have a more robust humerus than females, with pronounced muscle attachment sites and a triangular shaft cross section. Midshaft sections of the humeri of the males show the transition from the rounded juvenile cross section to the triangular adult cross section, as reflected in the contour of the growth marks. This shape change is produced by differential bone apposition of the periosteum, presumably triggered by sex hormones, as in humans, and influenced by changes in loading regime during puberty. This is the first report of puberty in a fossil amniote.
Topics: Male; Female; Animals; Reptiles; Aging; Sexual Maturation; Fossils
PubMed: 37352853
DOI: 10.1016/j.cub.2023.05.073 -
Aquatic Toxicology (Amsterdam,... May 2024Poly- and perfluoroalkyl substances (PFASs) are commonly used in various industries and everyday products, including clothing, electronics, furniture, paints, and many... (Review)
Review
Poly- and perfluoroalkyl substances (PFASs) are commonly used in various industries and everyday products, including clothing, electronics, furniture, paints, and many others. PFASs are primarily found in aquatic environments, but also present in soil, air and plants, making them one of the most important and dangerous pollutants of the natural environment. PFASs bioaccumulate in living organisms and are especially dangerous to aquatic and semi-aquatic animals. As endocrine disruptors, PFASs affect many internal organs and systems, including reproductive, endocrine, nervous, cardiovascular, and immune systems. This manuscript represents the first comprehensive review exclusively focusing on PFASs in amphibians and reptiles. Both groups of animals are highly vulnerable to PFASs in the natural habitats. Amphibians and reptiles, renowned for their sensitivity to environmental changes, are often used as crucial bioindicators to monitor ecosystem health and environmental pollution levels. Furthermore, the decline in amphibian and reptile populations worldwide may be related to increasing environmental pollution. Therefore, studies investigating the exposure of amphibians and reptiles to PFASs, as well as their impacts on these organisms are essential in modern toxicology. Summarizing the current knowledge on PFASs in amphibians and reptiles in a single manuscript will facilitate the exploration of new research topics in this field. Such a comprehensive review will aid researchers in understanding the implications of PFASs exposure on amphibians and reptiles, guiding future investigations to mitigate their adverse effects of these vital components of ecosystems.
Topics: Animals; Ecosystem; Water Pollutants, Chemical; Amphibians; Reptiles; Fluorocarbons
PubMed: 38564994
DOI: 10.1016/j.aquatox.2024.106907 -
Zoological Science Feb 2024Among amniotes, reptiles are ectothermic and are clearly distinguished from mammals and birds. Reptiles show great diversity not only in species numbers, but also in... (Review)
Review
Among amniotes, reptiles are ectothermic and are clearly distinguished from mammals and birds. Reptiles show great diversity not only in species numbers, but also in ecological and physiological features. Although their physiological diversity is an interesting research topic, less effort has been made compared to that for mammals and birds, in part due to lack of established experimental models and techniques. However, progress, especially in the field of neuroendocrinology, has been steadily made. With this process, basic data on selected reptilian species have been collected. This review article presents the progress made in the last decade, which includes 1) behavioral regulation by sex steroid hormones, 2) regulation of seasonal reproduction by melatonin and GnRH, and 3) regulation of social interaction by arginine vasotocin. Through these research topics, we provide insights into the physiology of reptiles and the latest findings in the field of amniote neuroendocrinology.
Topics: Animals; Neuroendocrinology; Social Behavior; Reptiles; Reproduction; Mammals
PubMed: 38587521
DOI: 10.2108/zs230060 -
European Journal of Protistology Apr 2024The zoonotic potential of the protist parasites Cryptosporidium spp. and Giardia duodenalis in amphibians and reptiles raises public health concerns due to their growing... (Review)
Review
The zoonotic potential of the protist parasites Cryptosporidium spp. and Giardia duodenalis in amphibians and reptiles raises public health concerns due to their growing popularity as pets. This review examines the prevalence and diversity of these parasites in wild and captive amphibians and reptiles to better understand the zoonotic risk. Research on Giardia in both groups is limited, and zoonotic forms of Cryptosporidium or Giardia have not been reported in amphibians. Host-adapted Cryptosporidium species dominate in reptiles, albeit some reptiles have been found to carry zoonotic (C. hominis and C. parvum) and rodent-associated (C. tyzzeri, C. muris and C. andersoni) species, primarily through mechanical carriage. Similarly, the limited reports of Giardia duodenalis (assemblages A, B and E) in reptiles may also be due to mechanical carriage. Thus, the available evidence indicates minimal zoonotic risk associated with these organisms in wild and captive frogs and reptiles. The exact transmission routes for these infections within reptile populations remain poorly understood, particularly regarding the importance of mechanical carriage. Although the risk appears minimal, continued research and surveillance efforts are necessary to gain a more comprehensive understanding of the transmission dynamics and ultimately improve our ability to safeguard human and animal health.
Topics: Animals; Humans; Giardiasis; Cryptosporidiosis; Cryptosporidium; Zoonoses; Giardia lamblia; Anura; Reptiles; Prevalence; Feces
PubMed: 38442435
DOI: 10.1016/j.ejop.2024.126066 -
The Veterinary Clinics of North... May 2024Pediatric exotic companion animal nutrition is a broad topic, spanning small mammals, reptiles, and birds. Little research has been performed focusing on the juvenile... (Review)
Review
Pediatric exotic companion animal nutrition is a broad topic, spanning small mammals, reptiles, and birds. Little research has been performed focusing on the juvenile life stages of these species because they are largely acquired by clients at the young adult stage. The information that does exist has been compiled by wildlife rehabilitators, commercial breeders, and/or exotic captive breeding programs, such as those that exist in zoologic facilities. In this article, we discuss natural history, feeding strategies, energy requirements, digestive physiology and diet digestibility, and key nutrients of concern as factors for determining an appropriate diet for pediatric exotic species.
Topics: Humans; Animals; Pets; Animals, Exotic; Animals, Wild; Reptiles; Mammals
PubMed: 38030515
DOI: 10.1016/j.cvex.2023.11.016 -
The Veterinary Clinics of North... Jan 2024Chelonian nutrition is still a young, but very important field of study. This article provides practical feeding advice for tortoises and freshwater and terrestrial... (Review)
Review
Chelonian nutrition is still a young, but very important field of study. This article provides practical feeding advice for tortoises and freshwater and terrestrial turtles. Areas covered include the different feeding ecology of different types of chelonians, their digestive physiology, growth rate, body condition scoring, an overview of what types of diets items can be used in captive diets, and examples of diets used for various species of chelonians.
Topics: Animals; Turtles; Fresh Water
PubMed: 37661549
DOI: 10.1016/j.cvex.2023.07.004 -
Gesundheitswesen (Bundesverband Der... Feb 2024
Topics: Animals; Dinosaurs; Germany
PubMed: 38378012
DOI: 10.1055/a-2220-7799