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Fluorescent age pigment accumulation as a determinant of chronological age in aquatic organisms
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|Title:||Fluorescent age pigment accumulation as a determinant of chronological age in aquatic organisms|
|Authors:||Hill, Kevin T.|
|Abstract:||Age pigments have been intensively studied by gerontologists hoping to define the biochemical processes involved in aging. More recently, age pigment accumulation has been studied by field biologists hoping to estimate chronological age of animals based on quantities of pigments measured in postmitotic tissues. The present research was conducted to evaluate methods used for extraction and measurement of fluorescent age pigments (FAP), describe patterns of FAP accumulation in two teleost fish species and develop multivariate age prediction models based on FAP content and other somatic variables, and determine the effects of some environmental and physiological variables on FAP variability. Evaluation of procedures for handling specimens and extracts revealed increases in FAP-like fluorophores in vitro in Oreochromis mossambicus brain, heart, and muscle tissues and their extracts with increased storage temperature (-20°C and above) and time, particularly in the chloroform/methonal solvent system. Ultrasonication of tissue homogenates greatly enhanced this effect and generated other fluorophores in solution. Fluorescence assay temperature also affected expression of FAP. Some or all of these effects of handling procedures may have produced variability of results reported from previous FAP studies. Nonpolar FAP extracted from o. mossambicus brain accumulated in an increasingly rapid manner with age. Nonpolar and polar FAP from Puntius conchonius brain leveled off with increasing age. FAP in £. conchonius heart increased linearly with age. Multiple regression analyses demonstrated the age-predictive value of FAP data for both species under controlled rearing conditions. FAP content and otolith dimension data consistently provided slightly stronger predictive models than somatic data alone. Temperature and body weight affected FAP content in P. conchonius brain and heart tissues. Brain FAP was inversely related to body weight, especially at the lower temperatures. Heart FAP was inversely related to body weight at 19°C, but positively related at higher temperatures. Increasing temperature decreased brain FAP, but increased heart FAP. Different levels of saturation of cellular lipid constituents at different temperatures may affect the potential for FAP formation via lipid peroxidation. FAP differences detected between non-sibling fish indicated genetic variation in the ability to control FAP genesis.|
|Description:||Thesis (Ph. D.)--University of Hawaii at Manoa, 1992.|
Includes bibliographical references.
xi, 162 leaves, bound ill. 29 cm
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|Appears in Collections:||Ph.D. - Zoology|
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