Physiology of the Cladocera
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The Physiology of Cladocera is a much-needed summary of foundational information on these increasingly important model organisms. This unique and valuable summary is based on the world's literature, including Russian research not widely available until now. It offers systematically arranged data on the physiology of Cladocera, assisting with explanation of their life and distribution, as well as discussion on directions of future research. Special expert contributions in genetics, immunology, and cytology round out the physiological chapters and provide comprehensive insight into the state of knowledge of Cladocera and its underlying mechanisms.
Cladocera crustaceans make up a significant part of the natural communities and biological productivity of fresh waters. In recent decades, they have become globally studied for many purposes, including systematics, genetic, molecular, ecological and evolutionary biology studies. They are also used as "sentinel" organisms for assessing water quality and the environment. In addition, the genome of Daphnia (a genus within Cladocera) was recently sequenced and published, giving this system a much wider exposure. It has also led to a rapidly growing awareness of the importance of understanding physiological processes as they relate to evolutionary and ecological genomics and ecogenomic toxicology.
Despite the increasing use of Cladocera in research and study, physiological background information on these creatures is fragmentary. Hundreds of unconnected publications have been accumulated on their physiology, and a synthesis and general representation of the literature has been much needed for the many researchers working with this organism. The Physiology of Cladocera stands alone as a valuable and comprehensive offering in this area for many researchers and students.
- Collects and synthesizes from the worldwide literature the state of knowledge of cladoceran physiology
- Forward-looking perspective incorporates information from the emerging technological worlds of genomics, cytology, chemical communication, and immunology
- Provides foundational information on Cladocera physiology for researchers in various fields, including conservation and evolutionary biology, genomics, ecology, ecotoxicology, and comparative physiology
suggested estimation of the condition of daphnias by scoring their oogenesis, embryogenesis, coloration, and oil drop status, as well as fullness of the gut. In the wide field of aquatic toxicology, the cladocera (mostly daphnids) are frequently PHYSIOLOGY OF THE CLADOCERA 15.6 CLADOCERA IN WATER QUALITY TESTING used as test objects or sentinel species (Lesnikov, 1967; Isakova and Kolosova, 1988) and Daphnia has been described as an excellent model organism for studying multiple environmental
PA, postabdominal lamella; RE, rectum; SUS, suspensory ligament; TLS, trunk limbs; TMM, 5c, transverse muscle of mandible; TMT, transverse mandibular tendon; VLM, ventral longitudinal trunk muscles. Source: Fryer (1974). PHYSIOLOGY OF THE CLADOCERA 3 1.2 GENERAL MORPHOLOGICAL BACKGROUND E O OL CG LM Ca HS Oe ODM A2M Mand DES TMT TMM A2M SUS 5c LGC L Endo S SA1 A2M TL1 Ht TL2 D Endo S C TTC Mxlle TL3 BP MG NC FCS FG FP3 200 µm A = ACAM P = PCAM FP4 TL5 EX3 EXS5 EXS3 EX4 TL4
source of EPA. Following feeding with EPA-free or EPAenriched Scenedesmus (green alga), 18:3ω3, 18:4ω3, 20:3ω3, and 20:4ω3 tissue concentrations were higher in D. galeata than in D. hyalina, indicating that assimilation and biosynthesis of PUFAs is higher in D galeata (von Elert, 2004). As Schlechtriem et al. (2006) summarized: Daphnia feeding on highly unsaturated fatty acids [HUFAs; e.g. EPA (20:5n3) or arachidonic acid (20:4n6)] become enriched with these fatty acids; docosahexaenoic acid
marine podonids ranges from 20.5 C to 20.76 C (depression of seawater at water salinities above 12m is 20.7 C to 21.39 C), whereas in Penilia it is 20.72 C (that of seawater is 20.99 C). Aladin also determined that marine cladocera support a lower osmotic concentration within the brood pouch, which favors normal development of the embryos. According to Aladin, marine cladocera swallow water and secrete ions: chlorine ions in the area of the nuchal organ in podonids, and from the epipodites
mechanical damage. In D. pulex, the envelope of resting eggs is 2.2 μm thick, whereas the outer wall of nonresistant eggs is only 0.35 μm (Seidman and Larsen, 1979). The shell composition of resting eggs of Daphnia includes crystalline calcium phosphate and magnetic material; their distinctive chemical composition and honeycomb structure are thought to ensure survival under harsh conditions (Kawasaki et al., 2004b). The distribution of elements over the integument of D. magna ephippia was found