National Repository of Grey Literature 8 records found  Search took 0.00 seconds. 
Physiological basis of extended longevity in termite kings and queens - is activation of telomerase mechanism linked with extended longevity of termites?
Pangrácová, Marie ; Hanus, Robert (advisor) ; Kodrík, Dalibor (referee)
- Extended longevity and high fecundity are two phenomena typical for reproductive castes (queens, eventually kings) of eusocial insects. In my thesis, we explore the hypothesis that the longevity of reproductives in the termite Prorhinotermes simplex is linked with the activation of the telomerase enzyme complex. Telomerase is well known for its life-extension functions, due especially to its capacity to prolong the telomeric ends of chromosomes. Therefore, we studied here the gene expression of: (1) the gene TERT coding for the catalytic subunit of the telomerase and (2) the genes of the main endocrine regulatory pathways, known to be responsible for the control of reproduction and longevity in insects. Expression dynamics of these genes were measured in sterile and reproductive castes of P. simplex during their development and sexual maturation. Based on our results obtained from the TERT expression analyses and their comparison with telomerase enzyme activities, we assume that the telomerase action in the long-lived reproductive individuals is regulated at a post-transcription level. Furthermore, we observed in reproductive castes a simultaneous upregulation of some transcription variants of vitellogenin and the genes for insulin signalling pathways. We can, therefore, conclude that in...
Juvenoids and juvenogens - possibilities of their use for pest management of herbivorous incect
Jedlička, Pavel ; Jarošík, Vojtěch (advisor) ; Kodrík, Dalibor (referee) ; Stejskal, Václav (referee)
INTRODUCTION In my PhD thesis I am engagedin determinationand evaluationof effects of selectedju- venoids andjuvenogens'ofvarious chemical structuÍeson model insect species.Thesecom- pounds were tested using topical and per os application on the red firebug, Pyrhocoris apterus L., and applied via the broad bean, Vicia faba L., root system on the pea aphid, Acyrthosiphonpisum Huris. Theq basedon result obtainedfrom theseassays,I considered the suitabi|iý of thesecompoundsfor aphidmanagementandtheir potentialimpact on aphid predatorybeetles(Coleopter4 Coccinelidae). RESULTS The most importantdataobtainedAom testson P. apterus andA. pisum I presentedin the articleJedličkaet a|.(2007): The systemiceffectsofjuvenoids on the red firebugPyrrřocois qterus and on the pea aphidAcyrthosiphonpisumwith dataon life tableresponse JeďičkaP., Hrdý I.,Kuldová J. andWimmerZ. PestManagementscience63' 102ó.1035 Abstract A series ofjuvenoid ďcohols and theř glycosidic derivatives (uvenogens),synthe. sized atthe lnstituteof Organic Chemistry and Biochemistry (IOCB) in hague, com- mercially usedjuvenoids and the naturď derivativesofjuvabione were evaluatedfor their systemic juvenilizing effect on the red firebug, Pyrrhocoris apterus L., and onthe pea aphid Ácyrthosiphonpisum Harris' A life table Íesponseexperimentwas desiped,...
The anti-oxidative stress response in Drosophila malanogaster involvement of adipokinetic hormone and adenosine
Zemanová, Milada ; Kodrík, Dalibor
The anti-oxidative stress response was studied in Drosophila melanogaster larvae and adults with mutation in genes of adipokinetic hormone (Akh), and adenosine receptor (AdoR(1)), and both these genes together (Akh(1) AdoR1 double mutant). To elicit the oxidative stress we administered paraquat (PQ) in food. Mortality tests revealed the double mutant Akh(1) AdoR(1) was more sensitive to PQ toxicity than either of the single mutants. The PQ administration significantly increased the Drome-AKH hormone level in control w(1118) and AdoR(1) larvae. On the contrary, PQ significantly increased expression of glutathione S-transferase D1 (GstD1) gene. It seems that both functional adenosine receptor and AKH itself are important for the proper control of the GstD1 gene expression under oxidative stress. On the other hand, differences in glutathione S-transferase (GST) activity among the strains, and between untreated and PQ treated groups were minimal. Next, the glutathione (GSH) level was significantly lower in all untreated mutant groups as compared with untreated control w1118 flies and declined further when the flies were treated with PQ. Thus, we demonstrated the important role of AKH and adenosine in control of anti-stress response elicited by PQ in D. melanogaster model.
Role of adipokinetic peptides in control of insect anti-stress reactions
Kodrík, Dalibor
Adipokinetic hormones (AKHs) control predominantly insect metabolism, but are involved also in a number of other activities. Recently, it was proven that AKHs participated also in the activation of antioxidant protection mechanisms: they increased a level of reduced glutathione and additionally, modulated the activity of catalase that reduces hydrogen peroxide to water and oxygen. It has also been found that AKHs participated on antistress reaction elicited by insecticides and increased the lethal effect of the insecticides alone. The results show that AKHs provide an initiation of the complex antistress response that involves both biochemical and physiological protective mechanisms.
Proteinase inhibitors from cockroaches: perspective of their use in the plant protection
Vinokurov, Konstantin ; Taranushenko, Yuliya ; Kludkiewicz, Barbara ; Kodrík, Dalibor ; Sehnal, František
The salivary glands and the gut of cockroaches contain both the digestive enzymes and their potential inhibitors. Four proteinase inhibitors were identified in the salivary glands of Nauphoeta cinerea and three of them were partially sequenced from the N-terminus. Coding sequences of corresponding cDNAs were established with the aid of RT PCR and degenerate primers. The sequences clearly encode inhibitors of serine proteinases.

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