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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Microbial nitrogen fixation in the digestive tract of Tipulidae larvae of different ecological and trophic groupsтезисы доклада
- Авторы: Chernysheva Angelina N., Kostina Natalia V.
- Сборник: Proceedings of the 20th International Congress on Nitrogen Fixation
- Тезисы
- Год издания: 2017
- Место издания: Univesidad de Granada Granada, Spain
- Аннотация: Intestinal symbionts capable for nitrogen fixation of crane-fly larvae of different ecological and trophic groups have been studied. Saprophagous larvae Tipula (Acutipula) maxima, bryophagous larvae Tipula (Savtshenkia) staegeri, and xylosaprophagous larvae Tipula (Pterelachisus) irrorata were chosen as the objects. Nitrogen fixing activity was measured by gas chromatography method and also by isotopic techniques. High rates of nitrogenase activity, up to 3.75 nmol C2H4/h/g, were determined in living larvae of T. maxima, which are comparable to the values of nitrogen fixing activity in the gastrointestinal tract of termites, 5.1 nmol C2H4/h/g (1). To determine the location of the highest nitrogen fixation, in the intestine content or on its walls, we measured the rates of nitrogenase activity in larvae with the released intestine. The actual nitrogen fixation, measured in such larvae, was 4.2 times lower. So it can be stated that the main agent of nitrogen fixation in the larvae is the intestine content, but not the microorganisms associated with its walls. To carry out isotope analysis, these larvae were kept in an atmosphere containing 3% gaseous 15N. The label content of 15N in the body and in the intestine was determined after incubation. A significant accumulation of labeled nitrogen was found only in the content and on the walls of the intestine that confirms data obtained by gas chromatography. Nitrogenase activity in other larvae was lower: in T.staegeri gastrointestinal tract it was 0.39 nmol C2H4/h/g; in T.irrorata intestinal tract,0.82 nmol C2H4/h/g; that is comparable with the data obtained for the xylosaprophagous larvae of beetles, Dorcus rectus, 1.25 nmol C2H2/h/g (2). Thus, nitrogen fixation was found in all the investigated groups of larvae; maximum levels were determined in saprophagous larvae; that confirms our hypothesis of significant microbial nitrogen fixation in larval nutrition.
- Добавил в систему: Костина Наталья Викторовна