China
Africa
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The Energetics of Fish Sperm Motility
Published in Claude Gagnon, Controls of Sperm Motility, 2020
There are two main patterns of fertilization that can be identified in fish: copulation and internal fertilization of oocytes in their follicules in the case of ovoviviparous species, and external fertilization with release of gametes in the water in oviparous species. The energy requirement by the spermatozoa is strongly related to the modes of fertilization which will be first described as an introduction to this chapter.
Profile of Toxic Pufferfish
Published in Ramasamy Santhanam, Biology and Ecology of Toxic Pufferfish, 2017
Reproduction: It is a oviparous species. Social and mating systems of this species are based upon female territoriality where polygyny results from males defending females occupying a certain territory (female-defense polygyny). All sexually mature females are territorial females. Neither parent guards the eggs which are laid in a nest located in the female’s territory. During breeding, territorial females perform the ‘caudal flexing with swollen abdomen display’ to signal courtship and readiness to spawn. The male acknowledges with no courtship or color displays but rather by visiting the sites frequently. The territorial female then begins pecking at the substrate in preparation for egg laying. The female initiates the spawning event by pressing her abdomen into the prepared site. The territorial male quickly lays his body across her caudal peduncle and both remained in this position for 5–10 sec. The male swims away after leaving the female beating her anal fin rapidly over the nest site to ensure fertilization of the eggs and to push the eggs deep into the algal substrate. All territorial males spawn with territorial females, depriving the bachelor males of the chance to copulate which nevertheless don’t interfere with the spawning between the territorial male and females.
Clinical Toxicology of Helodermatidae Lizard Bites
Published in Jürg Meier, Julian White, Handbook of: Clinical Toxicology of Animal Venoms and Poisons, 2017
The habitats of Heloderma are generally arid areas, deserts with rocks, shrubs and cacti, but the lizards may also be found in dry forests. They are mostly diurnal during spring and autumn, but are active at night in summer. The lizards retreat most of the time to burrows or rocky shelters to avoid the heat of the day. They are oviparous and lay clutches of up to 12 eggs. Their diet consists of eggs of groundnesting birds and of small mammals.
An overview of sex and reproductive immunity from an evolutionary/anthropological perspective
Published in Immunological Medicine, 2021
Yoshihiko Araki, Hiroshi Yoshitake, Kenji Yamatoya, Hiroshi Fujiwara
What are the implications of these research findings? The developmental strategy of using the placenta during embryonic growth to parasitize the mother’s body, absorb nutrients, and exchange gas for growth is indeed unnatural. Various organisms on Earth have become oviparous via sexual reproduction. A retroviral infection, such as the accident that befell a reptile species during the Triassic Period, is thought to have significantly changed the fate of this species. Subsequent climate change and meteorite falls are accidents that are a small part of the compositional process of the astronomical universe, and evolution itself seems to have no direction. Humans do not have a breeding season, and females ovulate once per month. Typically, the human uterus tolerates a single fetus. Other mammals, such as bears, give birth to small cubs that appear physiologically premature. Marsupials are unable to fully develop a fetus during pregnancy due to an immature placenta (called a yolk sac placenta) and raise their offspring in an external pouch.
The influence of the macular carotenoids on women’s eye and brain health
Published in Nutritional Neuroscience, 2023
Billy R. Hammond, Lisa Renzi-Hammond
In oviparous species, the yellow yolk of eggs serves as a visible reminder of the importance of carotenoids to prenatal development [79]. In humans, prematurity results in reduced LZ in retina [80] and brain [81]. Laie et al recently [82] studied the relation between myopia development and intake of L and Z during pregnancy. Myopia has become an important issue connected to modern life with some areas of the world approaching near total prevalence [83]. Mothers in the highest quartile of L and Z intake (measured as plasma levels at delivery) had children with 38% less risk of poor acuity when assessed three years later. The visual system matures rapidly in the first few years of life [84]. Intake of L and Z is particularly low during that time (Johnson et al,). Developmental studies with Rhesus monkeys (raised LZ deficient and then compared to normal controls) has shown that RPE cells are negatively affected by the absence of L and Z [85]. Rubin et al. found [86] that pre-term human infants given a control formula without LZ and omega-fatty acids showed negative changes in evoked electrogram readings compared to supplemented formula. The reduction in carotenoid levels in preterm babies may be due, in part, to increases in oxidative stress (supplemental LZ improves their antioxidant status [87]). Lutein levels in arterial cord blood positively correlate with Activin A in preterms [88], a neuroprotein often used as biomarker for brain development. All of these results point, less to using L and Z as a treatment for pre-terms with disease [89], but rather highlights the importance of LZ intake for mothers to promote normal healthy development [90,91].
Comparative transcriptome analysis reveals the effects of different feeding times on the hepatopancreas of Chinese mitten crabs
Published in Chronobiology International, 2023
Yingkai Xu, Baoli Zhang, Changyue Yu, Ziwei Hung, Nan Hu, Yuqiao Cai, Yingdong Li
This altered many metabolic pathways such as ether lipid metabolism and retinol metabolism in the hepatopancreas, which fully indicated that feeding E. sinensis at night could promote metabolism to a certain extent. Additionally, previous studies have shown that vitellogenin (Vtg) has immune defense functions and plays a key role in innate immunity in oviparous animals (Li et al. 2017); however, its involvement in innate immunity in the Chinese mitten crab remains to be investigated. Sun et al. (Sun et al. 2020) cloned and identified a hypothetical Vtg receptor, Vgr, from E. sinensis and found that its expression in the ovary was downregulated after ovarian stimulation by bacteria, which would lead to the accumulation of Vtg in the hemolymph. This suggested that the modulation of Vgr expression to control Vtg accumulation in the hemolymph could in turn influence immune responses. In addition, previous studies indicated that SIBD (Gai et al. 2010) and cyclophilin A (Song et al. 2009) might be involved in the innate immune defense of Chinese mitten crabs. These results suggested that feeding at night could enhance the metabolism and immunity of E. sinensis, thereby improving the immune response. The opposite trend was observed during the day, with reduced immunity compared with that observed at night. This conclusion was consistent with our previous findings comparing the effect of daily rhythms on the hemolymph of Chinese mitten crabs via comparative transcriptome analysis. However, the feeding time in our experiment may not be sufficient, hence determining the best feeding time and assessing the effect of changing the feeding rhythm of Chinese mitten crab on the expression of immune genes at the mRNA level remain warranted.