ETD

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Tesi etd-05172013-135858


Tipo di tesi
Tesi di dottorato di ricerca
Autore
SAGONA, SIMONA
URN
etd-05172013-135858
Titolo
Protein patterns and enzyme activities differences between healthy, ill and cured honey bees investigated by 2D electrophoresis and enzymatic assays
Settore scientifico disciplinare
BIO/10
Corso di studi
SCIENZE AGRARIE E VETERINARIE
Relatori
tutor Dott. Felicioli, Antonio
Parole chiave
  • proteomica
  • phenoloxidase
  • innate immune system
  • honey bees
  • glucoso ossidasi
  • glucose oxidase
  • fenolossidasi
  • Apis mellifera
  • api
  • proteomics
  • sistema immunitario innato
  • sistema immunitario sociale
  • social immune system
Data inizio appello
27/05/2013
Consultabilità
Completa
Riassunto
The honey bees are the most important commercial pollinators of those crops which depend on animal pollination for reproduction. Beekeeping is an eco-compatible activity that offers more than one type of production: honey, wax, royal jelly, pollen and propolis.
Beekeepers in Western countries have been reporting slow declines of bee stocks for many years, that seem unprecedented in recent history. This phenomena has been named "Colony collapse disorder" (CCD). It seems to be caused by a combination of various contributing factors rather than a single pathogen or poison.
The beekeeping of Apis mellifera L. in different types of beehive and the the import of honeybees from other countries due to globalization, have caused the presence of new pathogens. Beekeepers use treatments against these pathogens, in particular against the Varroa destructor, a mite that can in some cases cause the weakening of the colony. For these reasons we have decided to investigate the effects that some treatments, that the beekeepers generally use in their apiary, and some prevailing pathologies cause on the honey bees immune system. The aim of this work is to research new potential wellness indicators for honey bees. The old indicators which are family force, flight activity, pollen importation, are nowadays not sufficient anymore.
In our research we used the proteomic and enzymatic assay approaches. The 2D approach has been an immediate instrument to give a qualitative analysis of treated/ill samples compared to control samples. This analysis was used to investigate the effects of formic acid treatments. A small quantity of spots was identified by mass spectrometry but one protein was particularly interesting, glutathione-S-transferase. The 2D zymography approach was used to investigate the proteases present in samples infected with American foulbrood. At least 4 proteases were revealed in healthy prepupa samples and absent (P1, P2, P3) or partially present (P4) in diseased prepupa samples. These proteases could be grouped in two families: the serine proteases or the cysteine proteases. Analysis with 2D zymography have also revealed a protease inhibitor (trypsin or α-chymotrypsin inhibitor) that was present in the healthy prepupa samples but was absent in diseased prepupa samples.
Regarding to the phenoloxidase and glucose oxidase activities, some spectrophotometer and activity staining protocols were identified. Several analysis with treated/ill samples (adult or brood bees) revealed different phenoloxidase and glucose oxidase activities compared to the control samples (healthy or not treated samples). With the study of treated samples 30 days after the treatment by beekeepers, we could see a return of the enzymatic activity (phenoloxidase and glucose oxidase) to the initial values before the treatment. We can suppose that the honeybees have detoxification processes that eliminate the effects of the treatments. After a double stress represented by the infection with a parasite and a treatment, the honeybees presented a phenoloxidase or glucose oxidase activity frequently opposite or enhanced compared to a single stress scenario. We can suppose that after a stress the honey bees could be “prepared” to respond to a second stress.
A small pilot project was made with the aim to understand if the phenoloxidase and the glucose oxidase activities change in function of the season. The changes in the phenoloxidase and glucose oxidase activities were attributed particularly to the apiary condition, meteorological conditions, to the tasks which the honey bees carry out in a particular month and the cares of the beekeepers. The use of the glucose oxidase and its products (gluconic acid and hydrogen peroxide) against Paenibacillus larvae represents a new approach against this terrible pathology. It opens the possibility to try to “reinforce” the immune system of the honeybees against pathogens.