Dataset Information

A general model of hormesis in biological systems and its application to pest management.

ABSTRACT: Hormesis, a phenomenon whereby exposure to high levels of stressors is inhibitory but low (mild, sublethal and subtoxic) doses are stimulatory, challenges decision-making in the management of cancer, neurodegenerative diseases, nutrition and ecotoxicology. In the latter, increasing amounts of a pesticide may lead to upsurges rather than declines of pests, ecological paradoxes that are difficult to predict. Using a novel re-formulation of the Ricker population equation, we show how interactions between intervention strengths and dose timings, dose-response functions and intrinsic factors can model such paradoxes and hormesis. A model with three critical parameters revealed hormetic biphasic dose and dose timing responses, either in a J-shape or an inverted U-shape, yielding a homeostatic change or a catastrophic shift and hormetic effects in many parameter regions. Such effects were enhanced by repeated pulses of low-level stimulations within one generation at different dose timings, thereby reducing threshold levels, maximum responses and inhibition. The model provides insights into the complex dynamics of such systems and a methodology for improved experimental design and analysis, with wide-reaching implications for understanding hormetic effects in ecology and in medical and veterinary treatment decision-making. We hypothesized that the dynamics of a discrete generation pest control system can be determined by various three-parameter spaces, some of which reveal the conditions for occurrence of hormesis, and confirmed this by fitting our model to both hormetic data from the literature and to a non-hormetic dataset on pesticidal control of mirid bugs in cotton.

SUBMITTER: Tang S

PROVIDER: S-EPMC6731494 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A general model of hormesis in biological systems and its application to pest management.

Tang Sanyi S Liang Juhua J Xiang Changcheng C Xiao Yanni Y Wang Xia X Wu Jianhong J Li Guoping G Cheke Robert A RA

Journal of the Royal Society, Interface 20190821 157

Hormesis, a phenomenon whereby exposure to high levels of stressors is inhibitory but low (mild, sublethal and subtoxic) doses are stimulatory, challenges decision-making in the management of cancer, neurodegenerative diseases, nutrition and ecotoxicology. In the latter, increasing amounts of a pesticide may lead to upsurges rather than declines of pests, ecological paradoxes that are difficult to predict. Using a novel re-formulation of the Ricker population equation, we show how interactions b ...[more]

PMID: 31431187

Similar Datasets

Project description:Incorporating additional food supplements into the predators' diet complementary to the target prey has gained importance over the years due to its pertinence in achieving biological conservation and biological control. Studies by theoretical ecologists and mathematicians reveal that by providing appropriate quality and quantity of additional food to the predator, the system could be driven either towards co-existence of species (to an admissible interior equilibrium), thereby achieving conservation or towards elimination of either of species achieving bio-control eventually with time. However, one of the limitations of these studies is that the desired state is reached only as asymptotes which makes the outcomes of the studies not that practically viable. In this work, to overcome the limitation of asymptotes, we formulate and study a time optimal control problem for additional food provided system involving type III response using quantity of additional food as the control. The objective of the study is to reach the desired terminal state in minimum time. To that end, we first prove the existence of optimal solution using the Filippov's existence theorem and then establish the characteristics of the optimal control using the Pontryagin's Maximum Principle. Using the Hamiltonian minimization condition and the monotonicity property of the Hamiltonian with respect to the quantity parameter, we show that the optimal control strategy is of bang-bang type with a possibility of multiple switches in the trajectory in case of biological conservation and no switch in case of pest management. Since the additional food system exhibits contrasting behaviour with respect to quality additional food, we have considered multiple cases of quality as a part of this study and in each case, we fixed the quality parameter as constant. The theoretical results have been illustrated by performing numerical simulations for various cases relating to both biological conservation and pest management. The theoretical outcomes of this study are in line with ecological field observations.

Project description:RNA interference (RNAi) is a convenient tool to identify and characterize biological functions in organisms. Recently, it has become an alternative to chemical insecticides as a biologically based control agent. This promising technology has the potential to avoid many problems associated with conventional chemical insecticides. In order for RNAi application to be practical for field use, a major hurdle is the development of a cost-effective system of double-stranded RNA (dsRNA) production for a large quantity of dsRNA. A handful of research reports has demonstrated microbial-based dsRNA production using L4440 vector and HT115 (DE3) Escherichia coli for application to vertebrate and invertebrate systems. However, the dsRNA yield, production efficiency, and biological purity from this in vitro system is still unclear. Thus, our study detailed biochemical and molecular tools for large-scale dsRNA production using the microbial system and investigated the production efficiency and yield of crude and purified dsRNAs. An unrelated insect gene, green fluorescent protein (GFP), and an insect neuropeptide gene, pyrokinin (PK) identified from Drosophila suzukii, were used to construct the recombinant L4440 to be expressed in the HT115 (DE3) cell. A considerable amount of dsRNA, 19.5?µg/mL of liquid culture, was isolated using ultrasonic disruption followed by phenol extraction. The sonication method was further evaluated to extract crude dsRNA without the additional phenol extraction and nuclease treatments and also to reduce potential bacterial viability. The results suggest that the ultrasonic method saved time and costs to isolate crude dsRNA directly from large volumes of cell culture without E coli contamination. We investigated whether the injection of PK dsRNA into flies resulted in increased adult mortality, but it was not statistically significant at 95% confidence level. In this study, the microbial-based dsRNA production has potential for applied RNAi technology to complement current insect pest management practices.

Project description:The nature and cause of the division of organisms in superkingdoms is not fully understood. Assuming that environment shapes physiology, here we construct a novel theoretical framework that helps identify general patterns of organism persistence. This framework is based on Jacob von Uexküll's organism-centric view of the environment and James G. Miller's view of organisms as matter-energy-information processing molecular machines. Three concepts describe an organism's environmental niche: scope, umwelt, and gap. Scope denotes the entirety of environmental events and conditions to which the organism is exposed during its lifetime. Umwelt encompasses an organism's perception of these events. The gap is the organism's blind spot, the scope that is not covered by umwelt. These concepts bring organisms of different complexity to a common ecological denominator. Ecological and physiological data suggest organisms persist using three strategies: flexibility, robustness, and economy. All organisms use umwelt information to flexibly adapt to environmental change. They implement robustness against environmental perturbations within the gap generally through redundancy and reliability of internal constituents. Both flexibility and robustness improve survival. However, they also incur metabolic matter-energy processing costs, which otherwise could have been used for growth and reproduction. Lineages evolve unique tradeoff solutions among strategies in the space of what we call "a persistence triangle." Protein domain architecture and other evidence support the preferential use of flexibility and robustness properties. Archaea and Bacteria gravitate toward the triangle's economy vertex, with Archaea biased toward robustness. Eukarya trade economy for survivability. Protista occupy a saddle manifold separating akaryotes from multicellular organisms. Plants and the more flexible Fungi share an economic stratum, and Metazoa are locked in a positive feedback loop toward flexibility.

Dataset Information

A general model of hormesis in biological systems and its application to pest management.

Publications

A general model of hormesis in biological systems and its application to pest management.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets