Subproject: Neurophysiological and behavioral responses of different species to external magnetic field

The subproject „Neurophysiological and behavioral responses of different species to external magnetic field" deals with the effects of constant and alternating magnetic fields in insects, snail and mammals, with extra focus on the neuro-endocrine system. Electrophysiological studies in vitro and in vivo, biochemical analyses (oxidative stress state, nucleotide content, gaseous turnover, enzyme and receptor activities), histological analyses, and monitoring of development and behavior in selected model systems are planned. Obtained results will both contribute to the understanding of basic mechanisms of magnetoreception in evolutionary distant species and clarify the specific biological responses evoked by external magnetic fields.

Subproject: Responses of phytophagous pest insect to environmental stressors

The subproject is aimed at understanding plasticity in response to environmental stressors: magnetic fields, high temperatures, and chemicals (cadmium, plant allelochemicals and nutritional deficiency) and mechanisms of adaptation in insects (L. dispar, T. molitor, and others). Along with life history traits (survival, development duration, growth), the physiological parameters will be monitored: neuroendocrine responses, digestive reorganization and stress proteins-Hsp, antioxidative and detoxification enzymes. The results will clarify mechanisms of pest insect's adaptations to stressors and physiological responses that can be used as biomarkers sensitive to environmental changes.

The reaction of phytophagous insects to environmental changes (warming, chemical and electromagnetic pollution, etc.) is not passive. They respond to stress through neurohormonally mediated physiological changes and compensatory mechanisms to maintain homeostasis and overcome harmful effects of the stressors. The major focus of the subproject is to investigate mechanisms of adaptation to environmental stress in order to gain a better understanding of the role of physiological and behavioral plasticity in stress tolerance / resistance of phytophagous pest insects such as Lymantria dispar, Tenebrio molitor, and others. The results will predominantly be obtained from natural populations of L. dispar that are adapted to different levels of environmental stress. Insects populations will be taken from an oak forest (Quercus sp. – suitable host plant), a locust tree forest (Robinia pseudoaccacia - unsuitable host plant), and from an area that has industrial pollution.

Environmental variations, like other powerful stressors, first stimulate neuroendocrine reorganization, in particular, synthesis of stress protective hormones, and then hormonally mediated behavioral, physiological and metabolic changes. Any stress well known to increase energy demands, allocate resources to energy metabolism, and induce stress protective mechanisms, will consequently affect life history traits and the pest insect's adaptive value. Depending on stress intensity and duration, adaptive alterations in food consumption and utilization, digestion, absorption, antioxidative defence and detoxification may compensate for its harmful effects.

We will examine the effects of acute and chronic exposure to various stressors: 1. both constant and ELF magnetic fields; 2. chemicals (cadmium as a pollutant, tannic acid and quercetin as host plant defense allelochemicals and nutritional deficiency), and 3. high temperature (~35oC) alone or in combination with nutritional deficiency (variations of proteins and carbohydrates in diet). Along with life history traits (survival, development duration and growth) the following physiological parameters will be monitored after exposure to stressors: a) neuroendocrine responses i.e. activity of protocerebral neurosecretory neurons that produce biogenic amines and prothoracicotropic neurohormones (monoclonal antibody provided by Prof. Dr. Akira Mizoguchi, Nagoya University, Japan), and are involved in the regulation of energy metabolism, b) responses of digestive system: specific activitiesy and molecular isoforms of digestive enzymes (total protease, trypsin, lipase, leucine aminopeptidase, phosphatases, carbohydrases, amylase); histopathological changes in gut tissue after exposure to stressors; effects of the obesity hormone-ghrelin on the activity of digestive enzymes; immunocytochemical detection of ghrelin-like peptide in insect gut tissue, and 3. synthesis of stress proteins: heat shock proteins (Hsp 70 and Hsp 90), antioxidative enzymes (activity of superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase), glutathione content and detoxification enzymes (esterase, and glutathione-S-transferase).

Cooperators on the project:

Dr. Vesna Perić Mataruga, project leader
Dr. Jelica Lazarević
Dr. Milena Vlahović
Dr. Larisa Ilijin
Dr. Marija Mrdaković
Dr. Milena Janković-Tomanić
Dr. Dajana Todorović
Dragana Matić
Anja Gavrilović
Aleksandra Mrkonja
State University, Novi Pazar:
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