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16 - Neuroendocrine-immune interactions in neurotropic viral infections
- from Section III - Introduction: immunity, diagnosis, vector, and beneficial uses of neurotropic viruses
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- By C. Jane Welsh, Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA, Andrew J. Steelman, Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA, Amy N. Sieve, Department of Psychology, College of Liberal Arts, Texas A&M University, College Station, TX, USA, Wentao Mi, Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA, Robin R. Johnson, Psychology Department, College of Liberal Arts, Texas A&M University, College Station, TX, USA, Colin R. Young, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, and Department of Psychology, College of Liberal Arts, Texas A&M University, College Station, TX, USA, Thomas W. Prentice, Psychology Department, College of Liberal Arts, Texas A&M University, College Station, TX, USA, Mary W. Meagher, Psychology Department, College of Liberal Arts, Texas A&M University, College Station, TX, USA
- Edited by Carol Shoshkes Reiss, New York University
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- Book:
- Neurotropic Viral Infections
- Published online:
- 22 August 2009
- Print publication:
- 16 October 2008, pp 300-314
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Summary
Historical aspects of the neuroendocrine-immune connection
In order to understand the connection between the neuroendocrine and immune system, it is important to discuss the historical aspects of this relationship and the formulation of the concepts of homeostasis and stress. Claude Bernard in the 1860s developed the concept of “the milieu interne” to describe the balance of the internal milieu. In 1927, Cannon defined the fight or flight response to a threat and the concept of homeostasis as the physiological process by which an organism maintains a stable internal environment [1]. Then in 1936, Hans Selye observed that sick patients all had similar nonspecific symptoms: malaise, fever, and loss of appetite [2]. He proposed the general adaptation syndrome that states that when threatened by a threat or infection, the central nervous system (CNS) diverts the organism's energy reserves from nonessential functions (reproduction, growth) to functions that allow the organism to cope with the insult. Selye borrowed the term “stress” from the physical sciences to describe factors that upset homeostasis. He observed that stressed animals developed atrophy of the thymus, spleen, and lymph nodes and enlarged adrenal glands. Eventually, these effects were discovered to be the result of activation of the hypothalamic-pituitary-adrenal axis (HPA). Recently, McEwen has proposed the concept of allostatic load, which describes the cumulative effects of chronic stess that can result in dysregulation of multiple integrated physiological systems [3].
‘Junk’ DNA and phenotypic evolution in Silene section Siphonomorpha
- THOMAS R. MEAGHER, DENISE E. COSTICH
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- Journal:
- Genetics Research / Volume 90 / Issue 1 / February 2008
- Published online by Cambridge University Press:
- 20 February 2008, pp. 111-118
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- Article
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One of the long-standing mysteries in genomic evolution is the observation that much of the genome is composed of repetitive DNA, resulting in inter- and intraspecific variation in nuclear DNA content. Our discovery of a negative correlation between nuclear DNA content and flower size in Silene latifolia has been supported by our subsequent investigation of changes in DNA content as a correlated response to selection on flower size. Moreover, we have observed a similar trend across a range of related dioecious species in Silene sect. Elisanthe. Given the presence of sex chromosomes in dioecious Silene species, and the tendency of sex chromosomes to accumulate repetitive DNA, it seems plausible that dioecious species undergo genomic evolution in ways that differ from what one might expect in hermaphroditic species. Specifically, we query whether the observed relationship between nuclear DNA content and flower size observed in dioecious Silene is a peculiarity of sex chromosome evolution. In the present study we investigated nuclear DNA content and flower size variation in hermaphroditic species of Silene sect. Siphonomorpha, as close relatives of the dioecious species studied previously. Although the nuclear DNA contents of these species were lower than those for species in sect. Elisanthe, there was still significant intra- as well as interspecific variation in nuclear DNA content. Flower size variation was found among species of sect. Siphonomorpha for petal claw and petal limb lengths, but not for calyx diameter. This last trait varies extensively in sect. Elisanthe, in part due to sex-specific selection. A negative correlation with nuclear DNA content was found across populations for petal limb length, but not for other floral dimensions. We conclude that impacts of nuclear DNA content on phenotypic evolution do manifest themselves in hermaphroditic species, so that the effects observed in sect. Elisanthe, and particularly in S. latifolia, while perhaps amplified by the genomic impacts of sex chromosomes, are not limited to dioecious taxa.