Seasonal activity-profiles of enzymes involved in cryoprotectant biosynthesis in Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)

Abstract

Abstract. The activities of three enzymes involved in polyol biosynthesis (aldose reductase, AR; ketose reductase, KR; and polyol dehydrogenase, PDH) were studied in adult females of the linden bug, Pyrrhocoris apterus, collected from the field during 2005/2006. While the activities of three enzymes were low in reproductive females, activities greater by one or two orders were seen in reproductively arrested females. AR and KR showed similar seasonal trends in activity. Activities were low during diapause initation and later increased and stabilized during autumnal diapause development. Further increases of AR and KR activities were seen during low temperature quiescence and finally the activities sharply decreased during vernal resumption of direct development. The activity of PDH was relatively high (but fluctuating) during diapause, then decreased in quiescent insects and almost disapeared in reproductively active females. Insects collected in February were subjected to laboratory de-acclimation (exposure to high temperatures) followed by re-acclimation (exposure to low temperatures) which resulted in loss of activity in all three enzymes and no regain. High activities of AR, KR and PDH in reproductively arrested females thus conform well with their previously observed high capacity to synthesize and accumulate polyol cryoprotectants.

Between Control and Assistance: The Problem of European Accommodation Centres for Asylum Seekers

“…Those who spend extensive periods of time in the accommodation centres find it much more difficult to move into private rented accommodation and to find legal employment than those who spent the asylum procedure outside the centres. This was the experience of my interview partners, which is corroborated by numerous reports about integration of recognized refugees (Pořízek, 2004;Tollarová, 2008;Uherek et al, 2005).…”

“…Once in the centres, asylum seekers are not recognized as being able to take responsibility for their own affairs (see also Mackrill, 1996;Tollarová, 2008). Everyday matters such as accommodation, hygiene or their free time are arranged for them by the centres' employees.…”