1
|
Moshtaghi A, Vaziri H, Sariri R, Shaigan H. Polymorphism of MnSOD (Val16Ala) gene in pregnancies with blighted ovum: A case-control study. Int J Reprod Biomed 2017. [DOI: 10.29252/ijrm.15.8.503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
|
2
|
Gomiero A, Viarengo A. Effects of elevated temperature on the toxicity of copper and oxytetracycline in the marine model, Euplotes crassus: a climate change perspective. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2014; 194:262-271. [PMID: 25163430 DOI: 10.1016/j.envpol.2014.07.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 07/28/2014] [Accepted: 07/29/2014] [Indexed: 06/03/2023]
Abstract
Trace metals and broad-spectrum antibiotic drugs are common environmental contaminants, the importance of which is increasing due to global climate change-related effects. In the present study, the biological model organism E. crassus was first acclimated to five temperatures, from 25 °C to 33 °C, followed by exposure to nominal concentrations of copper, the antibiotic model compound oxytetracycline and mixtures of both, at increasing thermal conditions. Variations of temperature-related toxicity were assessed by two high-level endpoint tests, survival and replication rates, and two sublethal parameters: endocytosis rate and lysosomal membrane stability. The selected toxicants presented opposite behaviours as the protozoa's survival rates increased following an increasing thermal gradient in the oxytetracycline-related treatments, and a decline of tolerance in metal-related treatments was observed. Results of tests combining binary mixtures of tested toxicants showed a complex pattern of responses.
Collapse
Affiliation(s)
- A Gomiero
- Department of Science and Technological Innovation (DISIT), University of Piemonte Orientale, Via T. Michel 11, 15121 Alessandria, Italy; Institute of Marine Sciences (ISMAR), National Research Council (CNR), Largo Fiera della Pesca 1, 60125 Ancona, Italy.
| | - A Viarengo
- Department of Science and Technological Innovation (DISIT), University of Piemonte Orientale, Via T. Michel 11, 15121 Alessandria, Italy
| |
Collapse
|
3
|
Parsons P. Conservation strategies: adaptation to stress and the preservation of genetic diversity. Biol J Linn Soc Lond 2008. [DOI: 10.1111/j.1095-8312.1996.tb01447.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
4
|
LOESCHCKE VOLKER, KREBS ROBERTA, BARKER JSF. Genetic variation for resistance and acclimation to high temperature stress in Drosophila buzzatii. Biol J Linn Soc Lond 2008. [DOI: 10.1111/j.1095-8312.1994.tb00980.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
5
|
Parsons PA. The ecological stress theory of aging and hormesis: an energetic evolutionary model. Biogerontology 2007; 8:233-42. [PMID: 17473992 DOI: 10.1007/s10522-007-9080-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 12/30/2006] [Indexed: 10/23/2022]
Abstract
Free-living organisms normally struggle to exist in harsh environments that are nutritionally and energetically inadequate, where evolutionary adaptation is challenged by internal stresses within organisms and external stresses from the environment. The incorporation of environmental variables into aging theories such as the free-radical and metabolic rate/oxidative stress theories, is the basis of the ecological stress theory of aging and hormesis. Environmental variation from optimum to lethal extremes gives a fitness-stress continuum, where energetic efficiency, or fitness, is inversely related to stress level; in the evolutionary context survival is a more direct measure of fitness for assessing aging than is lifespan. On this continuum, the hormetic zone is in the optimum region, while aging emphasizes survival towards lethal extremes. At the limits of survival, a convergence of physiological and genetical processes is expected under accumulating stress from Reactive Oxygen Species, ROS. Limited ecologically-oriented studies imply that major genes are important towards limits of survival compared with the hormetic zone. Future investigations could usefully explore outlier populations physiologically and genetically, since there is the likelihood that genetic variability may be lower in those cohorts managing to survive to extremely advanced ages as found in highly stressed ecological outlier populations. If so, an evolutionary explanation of the mortality-rate decline typical of cohorts of the extremely old emerges. In summary, an energetic evolutionary approach produces a general aging theory which automatically incorporates hormesis, since the theory is based on a fitness-stress continuum covering the whole range of possible abiotic environments of natural populations.
Collapse
|
6
|
Parsons PA. Survival and longevity improvements at extreme ages: an interpretation assuming an ecological stress theory of aging. Biogerontology 2006; 8:225-31. [PMID: 17082910 DOI: 10.1007/s10522-006-9064-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Accepted: 08/15/2006] [Indexed: 11/25/2022]
Abstract
The primary determinant of survival during aging is the energetic efficiency and metabolic stability required to counter the accumulated internal and external stresses of a lifetime. Hence, genetically stress-resistant individuals should accumulate with age; frailer, less robust, less energetically efficient and less metabolically stable individuals should succumb in parallel. This selection process implies the accumulation of energetically efficient stress-resistant individuals with age to the exclusion of all others. High additive genetic variability for survival is expected under extreme circumstances, however there is limited evidence close to the absolute extremes of life that diversity may fall. At this stage, only a few highly adaptive, oxidative-stress-resistant and presumably somewhat homozygous genotypes should remain. Therefore a fall in variability may occur in these outliers, when frailer individuals are unable to cope and are eliminated at extreme ages. This process could provide an explanation of mortality-rate declines in domesticated (laboratory) and free-living populations of the extremely old. That is, mortality-rate declines may be an expectation from a process of genetic sorting resulting from the accumulated responses to environmental stress over time. Application of an ecological stress theory of aging, which combines the external stresses to which organisms are exposed with internal stresses, appears to be the prerequisite for this conclusion.
Collapse
|
7
|
Parsons PA. Energetic efficiency under stress underlies positive genetic correlations between longevity and other fitness traits in natural populations. Biogerontology 2006; 8:55-61. [PMID: 16847739 DOI: 10.1007/s10522-006-9028-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Accepted: 05/11/2006] [Indexed: 11/26/2022]
Abstract
Evolutionary relationships among fitness traits are considered in terms of the near-to-universal scenario of stressful environments leading to a resource-deficient and hence energy-deficient world. Fitness approximates to energetic (and metabolic) efficiency under this environmental model. When fitness is high, stress resistance (reducible to oxidative-stress resistance) and metabolic stability are maximal, and energy expenditure is minimal. Rapid development should then be favored followed by a long lifespan and high adult survival. Positive associations among diverse fitness or life-history traits are expected, controlled by stress-resistant 'good genotypes'. Heterozygotes tend to show higher energetic efficiency and hence higher fitness than do corresponding homozygotes under extreme environments, and to give parallel associations among life-history traits. Energy budgets under abiotic environments are pivotal for integrative evolutionary studies of life histories in natural populations.
Collapse
|
8
|
Parsons PA. Do Energetic Costs Underlie Variability and Evolutionary Potential Across Variably Stressful Environments? Isr J Ecol Evol 2006. [DOI: 10.1560/ijee_52_3-4_423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Stress can be viewed as an environmental probe that targets energy carriers, and hence can determine the energetic efficiency or fitness to survive. Thus, variability and evolutionary potential are interpreted in terms of the ecological scenario of predominantly stressful environments in the wild that restrict energy availability. This can explain how the observed variability of direct fitness traits is high at extremes of abiotic stresses, giving U-shaped curves for variability that incorporate more benign regions between the extremes. Some consistency with interpretations based upon conventional quantitative genetic techniques occurs, incorporating this ecological/energetic approach. However, investigations into the quantification of stress levels are required for more comprehensive assessments. Even so, evolutionary potential can in principle be investigated in terms of energetic consequences of the functional biology of organisms in their challenging habitats. This approach appears predictive for variability patterns of direct fitness traits as well as for developmentally more complex morphometric traits and for relationships among fitness traits in natural populations. That is, energetic costs are basic in determining evolutionary potential across variably stressful environments.
Collapse
|
9
|
Parsons PA. Environments and evolution: interactions between stress, resource inadequacy and energetic efficiency. Biol Rev Camb Philos Soc 2006; 80:589-610. [PMID: 16221331 DOI: 10.1017/s1464793105006822] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Revised: 05/19/2005] [Accepted: 05/19/2005] [Indexed: 11/06/2022]
Abstract
Evolutionary change is interpreted in terms of the near-universal ecological scenario of stressful environments. Consequently, there is a premium on the energetically efficient exploitation of resources in a resource-inadequate world. Under this environmental model, fitness can be approximated to energetic efficiency especially towards the limits of survival. Furthermore, fitness at one stage of the life-cycle should correlate with fitness at other stages, especially for development time, survival and longevity; 'good genotypes' under stress should therefore be at a premium. Conservation in the wild depends primarily on adaptation to abiotically changing habitats since towards the limits of survival, genomic variation is rarely restrictive. The balance between energetic costs under variable environments and energy from resources provides a model for interpreting evolutionary stasis, punctuational and gradual change, and specialist diversification. Ultimately, a species should be in an equilibrium between the physiology of an organism and its adaptation to the environment. The primary key to understanding evolutionary change should therefore be ecological, highlighting energy availability in a stressed world; this approach is predictive for various patterns of evolutionary change in the living and fossil biota.
Collapse
|
10
|
Abstract
It has been known for over a century that the dose-response curve for many micronutrients is non-monotonic, having an initial stage of increasing benefits with increased intake, followed by increasing costs as excesses become toxic. This phenomenon, termed Bertrand's rule, is widely assumed not to apply to caloric macronutrients. To date this assumption has been safe, owing to the considerable methodological challenges involved in coaxing animals to over-ingest macronutrients in a way that enables the effects of specific food components to be isolated. Here we report an experiment which overcomes these difficulties, to test whether the second phase (incurring costs with excessive intake) applies to carbohydrate intake by the generalist-feeding caterpillar Spodoptera littoralis. The results showed that excess carbohydrate intake caused increased mortality, thus extending Bertrand's rule to macronutrients.
Collapse
Affiliation(s)
- D Raubenheimer
- School of Biological Sciences, Ecology Evolution and Behaviour Section, University of Auckland, Private Bag 92019, Auckland, New Zealand.
| | | | | |
Collapse
|
11
|
Abstract
Assuming the stress theory of aging, longevity depends upon primary selection for stress resistance and metabolic efficiency. Predominantly based upon experimental studies in the insect Drosophila melanogaster, high genetic variability for fitness, especially mortality, occurs under extreme stress. Isofemale strains derived from the progeny of recently collected single inseminated Drosophila females from the wild should provide useful biological material for extrapolating to quantitative genetic studies in man. Furthermore, environments from the benign (hormetic) to the extreme can be incorporated. Survival to old age may depend upon genes for metabolic efficiency that respond to the environmental challenges of living as limits to adaptation are approached. Under this scenario the survival of longevity mutants in man to ages analogous to the extreme life spans found in some experimental organisms under benign or protected laboratory conditions is unlikely. More future emphasis is needed on genetic variation of longevity in natural populations of experimental organisms under an array of realistically stressful environments to act as an evolutionary model for longevity in our own species.
Collapse
|
12
|
Parsons PA. Radiation hormesis: challenging LNT theory via ecological and evolutionary considerations. HEALTH PHYSICS 2002; 82:513-516. [PMID: 11906140 DOI: 10.1097/00004032-200204000-00011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ecological and evolutionary considerations suggest that radiation hormesis is made up of two underlying components. The first (a) is background radiation hormesis based upon the background exposure to which all organisms are subjected throughout evolutionary time. The second and much larger component (b) is stress-derived radiation hormesis arising as a protective mechanism derived from metabolic adaptation to environmental stresses throughout evolutionary time especially from climate-based extremes. Since (b) > > (a), hormesis for ionizing radiation becomes an evolutionary expectation at exposures substantially exceeding background. This biological model renders linear no-threshold theory invalid. Accumulating evidence from experimental organisms ranging from protozoa to rodents, and from demographic studies on humans, is consistent with this interpretation. Although hormesis is not universally accepted, the model presented can be subjected to hypothesis-based empirical investigations in a range of organisms. At this stage, however, two consequences follow from this evolutionary model: (1) hormesis does not connote a value judgement usually expressed as a benefit; and (2) there is an emerging and increasingly convincing case for reviewing and relaxing some recommended radiation protection exposure levels in the low range.
Collapse
Affiliation(s)
- Peter A Parsons
- Department of Genetics and Human Variation, La Trobe University, Australia.
| |
Collapse
|
13
|
Abstract
Organisms in natural habitats are exposed to an array of environmental stresses, which all have energetic costs. Under this ecological scenario, hormesis for ionizing radiation becomes an evolutionary expectation at exposures substantially exceeding background. This conclusion implies that some relaxation of radiation protection criteria is worthy of serious consideration.
Collapse
Affiliation(s)
- P A Parsons
- School of Genetics and Human Variation, LaTrobe University, Victoria, Australia.
| |
Collapse
|
14
|
Abstract
The occurrence of U-shaped dose-response relationships (often termed hormesis) has been documented in numerous biological, toxicological, and pharmacological investigations. Many of the endpoints studied are of considerable significance to public health (e.g. body weight, cholesterol levels, ethanol consumption, longevity, cancer incidence, etc). Despite the fact that U-shaped dose-responses are widely and independently observed, little attempt has been made to assess this phenomenon in an integrative manner. This review provides an overview of the historical foundations of hormesis and a discussion of its definition within a mechanistic framework. The occurrence, generalizability, and biological significance of U-shaped dose-response relationships along with the concept of biological optimality are addressed.
Collapse
Affiliation(s)
- E J Calabrese
- School of Public Health & Health Sciences, Environmental Health Sciences Department, University of Massachusetts, Amherst, Massachusetts 01003-5712, USA.
| | | |
Collapse
|
15
|
Affiliation(s)
- P A Parsons
- School of Genetics and Human Variation, La Trobe University, Bundoora, Victoria 3083, Australia
| |
Collapse
|
16
|
Abstract
Non-linear fitness gradients with maxima between extremes are expected for any environmental variable to which free-living populations are exposed. For exceedingly toxic agents, including ionizing radiation, such deviations from linearity are close to zero exposure and are conventionally called hormesis. Accordingly, hormesis is an extreme version of the non-linear fitness gradients for general environmental stresses such as temperature fluctuations, for which maximum fitness occurs at the moderate temperature fluctuations to which free-living populations are most commonly exposed. Some metabolic reserves should occur under moderate temperature stresses because of the need for pre-adaptation enabling survival during exposure to occasional periods of more extreme stress, especially at species borders where selection for stress resistance is likely to be most intense. Because heat shock proteins are induced by all stresses, adaptation to extreme temperatures should translate into adaptation to other stresses. Consequently, metabolic reserves from adaptation to extreme temperatures in the past should translate into protection from correlated abiotic stresses, especially in human populations where modern cultural processes are now ameliorating exposure to extreme stresses. Ambient and man-made radiations of non-catastrophic dimensions should therefore lead to stress-derived radiation hormesis. Other stresses can, in principle, be incorporated into this model. Accordingly, evolutionary and ecological considerations suggest two components of hormesis in relation to ionizing radiation: background radiation hormesis based upon the background exposure to which all organisms on earth are subjected; and stress-derived radiation hormesis. Exposure under stress-derived radiation hormesis is considerably larger than under background radiation hormesis, so significant deleterious effects from non-catastrophic radiation normally may be impossible to detect. Suggestions are provided for testing such postulated deviations from the commonly assumed linear no-threshold (LNT) hypothesis for the biological consequences of exposure to radiation.
Collapse
Affiliation(s)
- P A Parsons
- School of Genetics and Human Variation, La Trobe University, Bundoora, Victoria 3083, Australia
| |
Collapse
|
17
|
|
18
|
Calabrese EJ, Baldwin LA. A general classification of U-shaped dose-response relationships in toxicology and their mechanistic foundations. Hum Exp Toxicol 1998; 17:353-64. [PMID: 9726531 DOI: 10.1177/096032719801700701] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The development of a comprehensive database of chemical hormetic responses (i.e., U- or inverted U-shaped dose-response relationships) using objective a priori study design, statistical and study replication criteria has recently been reported. An assessment of this database reveals the existence of a wide range of hormetic dose-response relationships including those demonstrating a direct stimulation or an overcompensation response to a disruption of homeostasis. These two broad types of hormetic responses are affected by temporal factors and display unique patterns of dose-range stimulation, magnitude of stimulatory response and relationship of the maximum stimulatory response to the NOAEL. A general classification of U-shaped dose-response relationships is proposed to provide a more organized framework to evaluate the highly distinctive and diverse hormetic responses within the context of establishing underlying biological mechanisms and exploring risk assessment implications.
Collapse
Affiliation(s)
- E J Calabrese
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts, Amherst 01003, USA
| | | |
Collapse
|
19
|
Behavioral Variability and Limits to Evolutionary Adaptation under Stress. ADVANCES IN THE STUDY OF BEHAVIOR 1998. [DOI: 10.1016/s0065-3454(08)60364-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|
20
|
Kieser JA. Falsification of a single-species hypothesis by using the coefficient of variation: a critique. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 1994; 95:95-7; discussion 98-102. [PMID: 7864995 DOI: 10.1002/ajpa.1330950111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- J A Kieser
- Department of Oral Pathology, Witwatersrand University, Johannesburg, South Africa
| |
Collapse
|
21
|
McKechnie SW, Geer BW. Micro-evolution in a wine cellar population: an historical perspective. Genetica 1993; 90:201-15. [PMID: 8119593 DOI: 10.1007/bf01435040] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The population of Drosophila melanogaster inside the wine cellar of Chateau Tahbilk of Victoria, Australia was found by McKenzie and Parsons (1974) to have undergone microevolution for greater alcohol tolerance when compared to the neighboring population outside the cellar. This triggered additional studies at Tahbilk, and at other wine cellars throughout the world. The contributions and interactions of researchers and the development of ideas on the ecology and genetics of this unique experimental system are traced. Although the ADH-F/ADH-S polymorphism was found to be maintained by selection in the Tahbilk populations, the selection is not significantly associated with alcohol tolerance. The environment inside the Tahbilk wine cellar is not as rich in ethanol as was originally anticipated, and selection that affects the alcohol dehydrogenase polymorphism may be more concerned with the relative efficiency with which ethanol is used as a nutrient by D. melanogaster. The synthesis and modification of lipids, particularly in membranes, appears to be important to alcohol tolerance. The studies of the Tahbilk population are at a crossroad. New experimental approaches promise to provide the keys to the selection that maintains the alcohol dehydrogenase polymorphism, and to factors that are important to alcohol tolerance and stress adaptation. From these research foundations at Tahbilk very significant contributions to our future understanding of the genetic processes of evolution can be made.
Collapse
Affiliation(s)
- S W McKechnie
- Department of Genetics and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | | |
Collapse
|
22
|
Abstract
Natural populations are normally exposed to substantial environmental stress. The consequences of stress include elevated metabolic costs and additive genetic variability. From the former, preferred habitats should be located in environments corresponding to minimum total energy expenditure. This tendency occurs in the field for behavioral adaptation of Drosophila to variable temperature (and humidity) conditions. Laboratory studies of resource preference in Drosophila suggest a low genetic variability. However, under more stressful field conditions, genetic variability should be higher. Habitat preference studies under stressful conditions therefore need to be emphasized in modeling situations in nature.
Collapse
Affiliation(s)
- P A Parsons
- Waite Institute, University of Adelaide, Australia
| |
Collapse
|
23
|
PARSONS PA. STRESS, EXTINCTIONS AND EVOLUTIONARY CHANGE: FROM LIVING ORGANISMS TO FOSSILS. Biol Rev Camb Philos Soc 1993. [DOI: 10.1111/j.1469-185x.1993.tb00999.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
24
|
|
25
|
Parsons PA. Developmental variability and the limits of adaptation: Interactions with stress. Genetica 1993. [DOI: 10.1007/bf02424518] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|