This mechanism prevents insensible water loss through the secretion of sweat, and corresponds to a saving up to 5 L of water every day.Īt the level of the kidney, the dromedary camel produces a low volume of highly concentrated urine, especially following dehydration, as a consequence of the highly efficient reabsorption of water. ![]() This 8☌ variation in body temperature allows a 750 kg camel to store 3.9 kJ of heat energy per kg of body weight for each 1C increase in body temperature, which is dissipated at night. However, it is water economy that is vital for survival in the desert, and, in the dromedary camel, this is achieved by minimal evaporative cooling (camels rarely sweat), low urinary output, water extraction from undigested food residues, and variation in body temperature from 34☌ at night up to 42☌ during the day. Water loss is extremely well tolerated in the dromedary camel whilst 12% would be fatal to non-desert mammals due to cardiac failure resulting from circulatory disturbance, the dromedary can survive up to 30% water loss. The dromedary is thus an ideal model for understanding the genomic and physiological mechanisms that enable mammals to survive in arid regions, and to integrate and reconcile the competing demands of thermoregulation and osmoregulation. Water balance is aggressively defended in all mammals, but this is all the more so in the homeostatic masterpiece that is the dromedary camel, which has a remarkable capacity to thrive in the hot, arid conditions of the Arabian and North African deserts, and to survive extended periods of dehydration during the summer months. This does not alter our adherence to PLOS ONE policies on data and materials sharing. There are no patents or products in development related to this manuscript. Additionally, BioEasy Sdn Phd provided support in the form of salaries for authors Y-L.t. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: This research was funded in part by the Leverhulme Trust. The Algerian camel genome files are available from the NCBI database ( ).įunding: This work was supported by the BBSRC ( BB/J01981X/1, BB/J015415/1 The Leverhulme Trust ( RPG-2017-287 The National Institute on Drug Abuse ( P30 DA018310 The University of Malaya ( UM.C/625/1/HIR/MOHE/MED/22 H-20001-E000086 EPSRC ( EP/K008250/1 and BioEasy Sdn Phd provided support in the form of salaries for authors Y-L.t. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All relevant data are within the paper and its Supporting Information files. Received: ApAccepted: ApPublished: June 18, 2019Ĭopyright: © 2019 Alim et al. PLoS ONE 14(6):Įditor: Genevieve Konopka, UT Southwestern Medical Center, UNITED STATES (2019) Seasonal adaptations of the hypothalamo-neurohypophyseal system of the dromedary camel. Identification of neuropeptides in the HNS and analysis of neuropeptide profiles in extracts from individual camels using mass spectrometry indicates that overall AVP peptide levels decreased in the HNS during summer compared to winter, perhaps due to increased release during periods of dehydration in the dry season.Ĭitation: Alim FZD, Romanova EV, Tay Y-L, Rahman AYbA, Chan K-G, Hong K-W, et al. ![]() Amongst the 171 transcripts found to be significantly differentially regulated (>2 fold change, p value <0.05) there is a significant over-representation of neuropeptide encoding genes, including that encoding AVP, the expression of which appeared to increase in summer. Based on our dromedary genome sequence, we have carried out an RNAseq analysis of the dromedary HNS in summer and winter. Interestingly, our electron microscopy studies have shown that the ultrastructure of the dromedary HNS changes according to season, suggesting that in the arid conditions of summer the HNS is in an activated state, in preparation for the likely prospect of water deprivation. One of the ways that this is achieved is through the actions of the antidiuretic hormone arginine vasopressin (AVP), which is made in a specialised part of the brain called the hypothalamo-neurohypophyseal system (HNS), but exerts its effects at the level of the kidney to provoke water conservation. The “ship” of the Arabian and North African deserts, the one-humped dromedary camel ( Camelus dromedarius) has a remarkable capacity to survive in conditions of extreme heat without needing to drink water.
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