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Candida and parasitic infection: Helminths, trichomoniasis, lice, scabies, and malaria
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Scabies is an ectoparasitic infestation caused by the human itch mite, Sarcoptes scabiei var hominis, for which humans are the only host in which replication can occur. Animal mites can infest human skin temporarily, but cannot replicate in humans and thus their infestation is self-limited. Adult female mites make characteristic serpentine burrows into the skin, usually between fingers and around the wrist in humans, where they lay 2 to 3 eggs per day as the burrow lengthens (61). Eggs hatch in 3 to 4 days to form larvae, which exit the serpentine burrow to dig a shallow molting pouch. Larvae develop into nymphs and then adults within 10 to 14 days inside the molting pouch. Adult male mites leave their molting pouch to burrow into the molting pouch of an adult female mite in order to fertilize the female who then continues to be fertile the remaining month of her life. Once impregnated, the adult female mite leaves the molting pouch to find a site to begin her own serpentine burrow and egg deposition, thus restarting the life cycle.
Women’s contributions to carcinology
Published in Frank Truesdale, History of Carcinology, 2020
Patsy A. McLaughlin, Sandra Gilchrist
The third of the trio of Dorothys is Dorothy Skinner (Fig. 21). Bom in Newton, Massachusetts, Dorothy received much of her early training in institutions within that state. She was tapped for Phi Beta Kappa in 1951 and obtained her bachelor’s degree in 1952 from Jackson College (Tufts University, Medford) where Ken Roeder kindled her early interests in science. Her work as an undergraduate was on the muscle receptor organ of the crayfish. Her early career aspirations were as aneurophysiologist. In the summers, as a graduate student at Harvard she attended the invertebrate biology and embryology courses at the Marine Biological Laboratory (MBL) at Woods Hole where she continued to expand her interests in decapod crustaceans under the guidance of Lew Kleinholz and Ted Bullock. It was during this graduate student period that two major developments occurred that influenced the rest of her career. She met another woman carcinologist, Dorothy Bliss, and through her was introduced to the land crab Gecarcinus lateralis. Her work then began to focus on understanding the molting processes. After receiving her Ph.D. in 1958, Skinner held a series of postdoctoral positions where she learned more about ways to study the physiology of molting and its control Her work was expanded on this subject to include exciting new studies of the DNA structure of G. lateralis.
Pineal Gland
Published in Paul V. Malven, Mammalian Neuroendocrinology, 2019
The strongest evidence in support of endogenous free-running circannual rhythms involves the molting activity of certain species of birds (Gwinner, 1986). During maintenance of such birds in a constant 10L:14D photoperiod for 7 years, there occurred nine complete cycles of pre-nuptial and post-nuptial molting. This molting activity recurred on the average every 9–10 months. Because the molting did not occur at a consistent time of the year, it could not have been entrained by unregulated seasonal elements.
Comparative transcriptome analysis reveals the impact of the daily rhythm on the hemolymph of the Chinese mitten crab (Eriocheir sinensis)
Published in Chronobiology International, 2022
Changyue Yu, Baoli Zhang, Zhiyuan Zhang, Simiao Wang, Tingyu Wei, Lisong Li, Yingying Zhao, Hua Wei, Yingdong Li
Consistent with the functional enrichment analysis of DEGs, some of the genes related to the molting process were upregulated at 18:00 h, indicating that E. sinensis may molt at night. In crustacean decapods, the exoskeleton is the main component of chitin, and its metabolism is the most critical process of growth and development (Hans and Lars 2003). Here, genes related to exoskeleton metabolism, such as those for chitinases, chitin deacetylase, and chitin synthase, were found in clusters 1, 2, and 3 in the transcriptional trend map under the daily cycle. However, the gene expression trends of these three clusters were not the same, and this may be because chitin is laid down daily in a molt rhythm, resulting in daily cycles that are numerically related to the molting time (Abehsera et al. 2014). However, the time of molting can be influenced by the day–night process (Robert and Gabriele 2013). The present findings showed that the molting-related gene encoding farnesoic acid O-methyltransferase (cluster 9) has higher expression levels at midnight and relatively low expression level during the daytime. Furthermore, the retinol metabolism and steroid hormone biosynthesis pathways were significantly upregulated at 24:00 h compared with those in the 12:00 h group. However, previous research has confirmed that the molting process of crustaceans occurs mainly at night (Iribarne et al. 2009). From these results, we speculate that E. sinensis molts mainly at night, consistent with the findings of a previous transcriptomic study of its eyestalk (Li et al. 2019).
Advances in thermal physiology of diving marine mammals: The dual role of peripheral perfusion
Published in Temperature, 2022
Arina B. Favilla, Markus Horning, Daniel P. Costa
Future work should address other conflicting physiological demands that require peripheral perfusion and their interactions with thermoregulation. For instance, molting is a necessary phenomenon that requires perfusion of the skin to replace old skin and fur. The form and phenology of molting vary widely, from annual catastrophic molting to continuous gradual molting. It often depends on whether animals can find thermal refugia to minimize the energetic costs of increased heat loss associated with skin perfusion [136–139]. Similarly, wound healing requires perfusion of the injured site, potentially leading to a tradeoff in short-term energetic costs and long-term health and survival. Haul-out periods for amphibious species, or seasonal residency at warmer latitudes for long-distance migrators, allow for temporal separation of these physiological demands that would otherwise increase thermoregulatory costs. Finally, unlike fur, blubber is a living tissue that serves as an energy store, and depositing or metabolizing lipid stores also requires perfusion of this layer [32,140,141]. Thus, in addition to the dual role associated with thermoregulation and diving that was the primary focus of this review, peripheral perfusion is critical for many other physiological processes. How these conflicting demands interact with each other warrants further investigation.
How relevant are in vitro culture models for study of tick-pathogen interactions?
Published in Pathogens and Global Health, 2021
Cristiano Salata, Sara Moutailler, Houssam Attoui, Erich Zweygarth, Lygia Decker, Lesley Bell-Sakyi
The first reported tick tissue cultures comprised tissue fragments or organs with some limited cell outgrowth or proliferation and a survival time of just a few days [8,9]. Techniques for longer-lived and repeatable primary ixodid tick tissue and cell cultures suitable for pathogen propagation were first developed in the 1960s [10–15]. These cultures, derived from developing adult ticks dissected out from the molting nymphal integument, comprised viscera, adherent tissue fragments and cellular outgrowths, and survived for up to 25 weeks. The introduction of trypsin as a dispersing agent facilitated production of cell monolayers [16,17]. Some cell proliferation was observed, but continuous growth was not achieved. The main disadvantages of primary cultures as experimental models were the need for a constant supply of molting nymphal ticks, the need for the ticks to be dissected aseptically and the lack of reproducibility. Attention was soon turned to tick eggs as a more easily handled source of material for generation of reproducible primary cultures [18] (Figure 1), and this approach resulted in the first successful series of subcultures up to passage 14 [19]. The painstakingly achieved improvements in techniques and culture media over the first two decades of tick tissue culture were about to yield dividends in the form of cell lines.