Laboratory of Insect Diapause
Mission
Diapause is a central element of insect life-cycle. It allows insects to overcome harsh seasons and exploit fluctuating resources. Our aim is to contribute to basic understanding of the molecular, biochemical and physiological mechanisms of diapause and associated expression of high tolerance to abiotic environmental stressors. We focus on two major topics: (1) the role of biological circadian clocks in the perception and transduction of photoperiodic information into the overt manifestation of diapause (stop of development, cell cycle arrest, accumulation of energy reserves, low metabolic rate, altered gene expression, metabolic switch); (2) the principles of seasonally acquired high cold tolerance (changes in metabolomic profiles, accumulation of cryoprotective compounds, restructuring of membrane composition, adjustments of membrane function, expression of heat shock proteins). Our results serve practical purposes of forecasting the timings of seasonal activities and estimation of overwintering survival in populations of pest species.
Staff
Head
Researchers
Technicians
Students (PhD.)
Students
Former PhD. Students
- Alena Kobelková (2010)
- Michaela Tollarová-Borovanská (2009)
- Martin Šlachta (2002)
Current research projects
Clock genes and diapause
We study putative functional participation of known clock genes timeless, period and others in the perception of day length and induction of diapause. We clone clock genes in the model species with clear manifestation of diapause and assess their expression patterns using qRT-PCR and other techniques. We disrupt gene expression using RNAi and localize clock neurons using immunocytochemistry. We exploit mutant and transgenic insect lines with disturbed diapause response and observe their photoperiodic and circadian phenotypes. Model species: Chymomyza costata, Pyrrhocoris apterus.
PI: V. Kostal
Collaborations: D. Dolezel, I. Sauman, M. Hodková, R. Závodská (Ceské Budejovice, CZ); D.L. Denlinger (Columbus, Ohio, USA); K. Shimada (Sapporo, Japan).
Mechanisms of insect cold tolerance and long term cryopreservation
We analyze physiological nature of high cold tolerance in diapausing insects. Knowledge on these mechanisms can serve as a basis for development of long-term cryopreservation techniques for insects or other biological materials. Laboratory-acclimation protocols are used to trigger/stimulate high cold tolerance. We focus on changes in membrane phospholipid composition which affect the membrane fluidity and phase behaviour and, consequently, allow to maintain membrane functions or protect its integrity at low temperatures. In addition, we study changes of gene expression which result in metabolic switching and synthesis of protective substances such as polyols or heat shock proteins. Model species: Pyrrhocoris apterus, Chymomyza costata, Drosophila melanogaster.
PI: V. Kostal
Collaborations: P. Simek (Ceske Budejovice, CZ); M. Holmstrup (Aarhus, Denmark); D. Renault (Rennes, France).
Physiology of insect pests' overwintering
We follow the course and the success of overwintering in selected insect pest species in the field. We assess the seasonal timings of diapause induction, initiation, termination and the onset of spring activity. We measure a set of physiological parameters which correlate and/or are causally involved in cold tolerance. We use various techniques (supercooling point, vapour pressure and Clifton nanoliter osmometers, differential scanning calorimetry, respirometry, analysis of metabolites using GC-MS, LC-ESI-MS). Model species: Ips typographus, Cydia pomonella, Ostrinia nubilalis
PI: V. Kostal
Collaborations: P. Dolezal, P. Simek (Ceské Budejovice, CZ); G. Grubor-Lajsic (Novi Sad, Serbia).
