Lower vertebrates

Brain mechanisms of behaviour in lower vertebrates. Edited by P.R. Laming... 

The lower vertebrates then possessed a useful nasal device which had already been utilised by their predecessors as a social chemical detector. Air breathing meant that their nasal air-flow was relatively weak in the absence of the pulling power exerted by lungs which... 

Gutzke, 1999). The AOS of lower vertebrates seems to retain the ability to act as an early warning system in the avoidance of enemies and in the location of prey. This suggests that on land the basis for subsequent elaborations of social chemosignals could have been the simple proteins of immediate survival value. 

Shostak, S. and Tammariello, R. V. (1969), Supernumerary heads in Hydra viridis, in C. J. Dawe and J. C. Harshbarger (Eds), Neoplasms and Related Disorders of Invertebrate and Lower Vertebrate Animals, National Cancer Institute Monograph, 31, 739-750. 

Otolith—a tiny bony structure in the inner ear of lower vertebrates. 

Abstract. Recent experimental results in culture and in vivo are summarized that show the existence of developmental relationships between cells that build up blood vessel walls and some previously unrelated tissues and organs. It was formerly demonstrated, in lower vertebrates as well as mammals, including humans, that discrete subsets of blood-forming endothelial cells play a key role in the emergence of the definitive hematopoietic system. We have also documented the existence in human skeletal muscle of endothelium-borne, extremely potent myogenic progenitor cells. Einally, we have characterized and purified perivascular cells - or pericytes - from human tissues and... 

Various specialized structures may aid in sampling air or improving directional smelling. The elephant s tnmk can be seen as an olfactory periscope tube-nosed bats Murina and Harpiocephalus spp., Vespertilionidae) and hammerhead sharks (Sphyrnidae) represent bizarre examples of specialized olfactoiy anatomy. Nostrils of lower vertebrates tend to be farther apart than those of higher vertebrates that have more flexible heads and necks (Stoddart, 1983). 

IgM may be regarded as the most primitive of the immunoglobulins. It is the first antibody produced in response to an antigen in the primary immune response. In human gestation it is the first Ig to be produced in the fetus in response to infection, e.g., syphilis, malaria, toxoplasmosis, and rubella in some of the lower vertebrates it is the only immunoglobulin as yet detected. 

Okamura H, Miyake S, Sumi Y et al 1999 Photic induction of mPer1 and mPerl in Cry-Ae cieuat mice lacking a biological clock. Science 286 2531-2534 Oshima N 2001 Direct reception of light by chromatophores of lower vertebrates. Pigment Cell Res 14 312-319... 

This chapter has mainly focused on the categories of compounds used to address various medical conditions, their mode of action, and side effects. UntH recently, research on the use of PPCPs has mainly focused on their beneficial and adverse effects on the end users— both humans and livestock. The mode of action of these compounds in these target organisms has mostly been well studied, with little regard to whether similar targets exist in lower vertebrates and invertebrates. 

Itina, N.A. (1970). Structure and function of muscle fibrils in lower vertebrates (In Russian). Uspekhi Sovremennoy Biologii 70,286-304. 

Johnston, I.A. (1983). Comparative studies of contractile proteins from the skeletal and cardiac muscles of lower vertebrates. Comparative Biochemistry and Physiology 76A, 439-445. 

Musatov, A.P. (1993). Van t Hoff temperature coefficient for energy metabolism in lower vertebrates (In Russian). Gydnobiologicheskii Zhumal 29,77-80. 

Plisetskaya, E.M. (1975). Hormonal Regulation of the Carbohydrate Metabolism in Lower Vertebrates (In Russian). Nauka, Leningrad, 209 pp. 

AP Poland University of Wisconsin-Madison, Madison, Wl Seek to characterize the Ah receptor in the mouse and is screening lower vertebrate and invertebrate species for the presence of the Ah receptor... 

In "Handbook of Sensory Physiology III/3. Electroreceptors and Other Specialized Receptors in Lower Vertebrates" A. 

Most work has centred on cyclophyllidean species whose larvae develop in mammals. Few studies have been made on the other cestode orders, such as the Pseudophyllidea whose larvae develop in lower vertebrates, especially fish, amphibia and reptilia. Apart from the H. nana/rodent system, discussed earlier, the most studied species have been those which are either readily maintained in laboratory animals or are of medical, veterinary or economic importance, i.e. Echinococcus granulosus, E. multilocularis, Mesocestoides corti, Taenia crassiceps, T. hydatigena, T. multiceps, T. ovis, T. saginata and T. solium. The account given here has been restricted largely to these species. 

Freeze-tolerance is also noted in less extreme, cold temperate environments, in which certain species elect to become solid-state even when their neighbors mount successful freeze-avoidance strategies of the types just described for terrestrial insects like D. canadensis. In fact, even the latter species has been observed to rely on freeze-tolerance under extreme conditions. The adoption of freeze tolerance in winter is noted in a wide variety of animal taxa, including numerous arthropods and even a few lower vertebrates, the freeze-tolerant frogs and reptiles (see Storey, 1990, for review). Plants, too, may spend much of the winter in a solid-state condition (Griffith and Antikainen, 1996). 

Bennett, A.F. (1978). Activity metabolism of the lower vertebrates. Annu. Rev. Physiol. 40 447-469. 

Gap junctions provide in the nervous system the structural correlate of one class of electrical synapses, characterized by very close apposition between the presynaptic and postsynaptic membranes. It should be noted, in this respect, that different junctional specializations can mediate different forms of electrical transmission between neurons (Bennett, 1997). Electrical synapses transmit preferentially, but not exclusively, low-frequency stimuli, that allow the rapid transfer of a presynaptic impulse into an electrical excitatory potential in the postjunctional cells. Electrical transmission, via the intercellular channels, can be bidirectional. The widely held opinion that electrical transmission is characteristic of lower vertebrates probably derives from the large cell systems in which electrical synapses were identified in the initial period of intracellular recording (reviewed by Bennett, 1997). Contradicting this view, electrotonic coupling between neurons has now been demonstrated in many areas of the mammalian central nervous system and has been implicated in neuronal synchronization. Gap junctional intercellular communication can occur between glial cells, glia and neurons, as well as between neurons. 

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