MORPHOLOGICAL AND HISTOLOGICAL CHANGES IN DEVELOPMENT OF HYPOPHARYNGEAL GLANDS IN HONEYBEE (Apis mellifera carnica)

Hipofaringealne žleze proizvajajo in izločajo sestavine matičnega mlečka, ki je pomembna hrana za zalego in matico. Mlade delavke imajo razvite žleze z velikimi acinusi, ki aktivno izločajo sekret. Med seboj smo primerjali delavke iz rednika in delavke iste starosti iz čebelje družine. Ugotovili smo, da so imele krmilke iz rednika v starosti nad 15 dni večji premer žleznih acinusov. Aktivno izločanje sekreta se podaljšuje s starostjo (do 27 dni) pri krmilkah iz rednika, ki ostajajo v družini in intenzivno oskrbujejo ličinke v matičnih lončkih. Opisali smo morfološke in histološke značilnosti žlez pri delavkah v razvojni stopnji bube, pri dolgoživih, zimskih čebelah in pri delavkah krmilkah v starosti 1 do 27 dni. V drugem delu poskusa smo različno stare delavke v kletkah tretirali z imidaklopridom, diazinonom ali kumafosom v časovnem obdobju za 24, 48 ali 72 ur. Po zaključenem tretiranju smo izmerili velikost premera žleznih acinusov in ugotovili značilen vpliv tretiranja na zmanjšano velikost žlez (p < 0,05). Delavke, ki so bile dlje časa (48 in 72 ur) izpostavljene tretiranju, so imele manjše žleze v primerjavi s kontrolno skupino netretiranih delavk. V žleznih acinusih smo lokalizirali stresne proteine (Hsp 70 ali Hsp 90) in določali stopnjo celične smrti. Pri delavkah, ki so bile tretirane s kumafosom ali diazinonom, smo pogosteje lokalizirali Hsp v celičnem jedru in citoplazmi, kot pri delavkah, ki so bile tretirane z imidaklopridom. Ugotovili smo, da se Hsp lokalizirajo različno glede na vrsto pesticida in starost čebel. Pri delavkah, ki so bile tretirane s kumafosom, smo ugotovili povečano stopnjo apoptotske celične smrti, po tretiranju z imidaklopridom je bila v žleznih celicah nakazana tudi nekroza. V drugi starostni skupini (7 do 12 dni) delavk je bila stopnja celične smrti po 48 urah tretiranja z imidaklopridom okoli 50-odstotna in se je po 72 urah pojavila v jedrih vseh celic. Hsp smo določili tudi v žleznih celicah netretiranih delavk in ugotovili, da je celična smrt ostala na stopnji običajne obnove celic (do 10 odstotkov) pri delavkah iz vseh štirih starostnih skupin. Pesticidi, ki smo jih uporabili v poskusu, so pri delavkah medonosne čebele povzročili povečano stopnjo odmiranja celic žleznih acinusov.Hypopharyngeal glands produce and secrete the components of rojal jelly which is the most important food for brood and queen. In young workers, the glands are well developed with large actively secreting acini. The workers from the breeder colony were compared to workers from the honeybee colony. We found that nurses from the breeder colony aged over 15 days had larger acini diameter. Active gland secretion is extended with age (until 27 days) in the nurse workers which seem to stay in the hive and intensivelly feed the brood in the queen cells. The morphological and histological characteristics of the hypopharyngeal glands were described in worker pupa, winter bees and in nurse workers aged 1 to 27 days. In the second part of our research, the workers were treated with imidaclopride, diazinon, or coumaphos for 24, 48 and 72 hours. After the treatment we measured the size of the acinar diameter and found significant effect of treatment on the decreased size of the acini (p < 0.05). In the workers that were exposed to the treatments for longer time periods (48 and 72 h), the glands were smaller comparing to the glands in control group of untreated workers. Hsps (Hsp 70 or Hsp 90) were localised in the glandular acini and the level of cell death was determined. In the workers treated with coumaphos or diazinon, the Hsps were more frequently localised in the cell nuclei and cytoplasm in comparison to imidacloprid treated workers. Hsps seem to localise differently, depending on a pesticide and age of bees. In coumaphos-treated workers we detected increased apoptotic cell death and in imidacloprid-treated workers the necrosis was indicated. In the second age-group (7–12 days) the level of cell death was found 50 % after 48 h of treatment with imidacloprid, and encreased after 72 h of treatment when all of the cell nuceli were found positive. In the untreated workers, the Hsps were found in the glandular cells and the normal cell renewal stayed at the low level (< 10 %) in workers of all four age-groups. The pesticides used in our experiments caused a high level of the cell death in the glands cells of the treated honeybee workers