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861.
The role of the adipokinetic hormone (AKH) in the control of protease, amylase and lipase activities is examined using the cockroach Periplaneta americana and the fruit fly Drosophila melanogaster as model species. The effects of Peram‐CAH‐I and ‐II on the activity of cockroach digestive enzymes in the gastric caeca and midgut are measured both in vivo and in vitro. The results show the activity of proteases, amylases and lipases in both parts of the gut: amylase activity is higher in the gastric caeca than in the midgut; lipase activity presents the opposite trend; and protease activity is similar in both organs. The applied hormones stimulate the activity of all digestive enzymes, although this stimulation is not uniform; AKHs affect enzymes selectively, and in some cases unequally, in the gastric caeca and midgut. No substantial differences between Peram‐CAH‐I and ‐II stimulation are recorded. The in vitro results demonstrate that AKH stimulates digestive enzyme activity directly. In agreement with the cockroach results, enzymatic activity in D. melanogaster larvae producing nonfunctional AKH is lower than that in the larvae with ectopically expressed Akh gene, where enzyme activity reaches or even exceeds that of the controls. Overall, the results demonstrate the active role of AKHs in the stimulation of digestive enzyme activity in insects. 相似文献
862.
Magdalena Niedziakowska Karolina Doan Marcin Grny Maciej Sykut Krzysztof Stefaniak Natalia Piotrowska Bogumia Jdrzejewska Bogdan Ridush Sawomira Paweczyk Pawe Mackiewicz Ulrich Schmlcke Pavel Kosintsev Daniel Makowiecki Maxim Charniauski Dariusz Krasnodbski Eve Ranname Urmas Saarma Marine Arakelyan Ninna Manaseryan Vadim V. Titov Pavel Hulva Adrian Blescu Ralph Fyfe Jessie Woodbridge Katerina Trantalidou Vesna Dimitrijevi Oleksandr Kovalchuk Jarosaw Wilczyski Theodor Obad Grzegorz Lipecki Alesia Arabey Ana Stankovi 《Journal of Biogeography》2021,48(1):147-159
863.
ukasz Mazurek Dmitry Ghilarov Elizabeth Michalczyk Zuzanna Pakosz Mikhail Metelev Wojciech Czyszczo Karolina Wawro Iraj Behroz Svetlana Dubiley Roderich D Süssmuth Jonathan G Heddle 《Nucleic acids research》2021,49(3):1581
DNA gyrase, a type II topoisomerase found predominantly in bacteria, is the target for a variety of ‘poisons’, namely natural product toxins (e.g. albicidin, microcin B17) and clinically important synthetic molecules (e.g. fluoroquinolones). Resistance to both groups can be mediated by pentapeptide repeat proteins (PRPs). Despite long-term studies, the mechanism of action of these protective PRPs is not known. We show that a PRP, QnrB1 provides specific protection against fluoroquinolones, which strictly requires ATP hydrolysis by gyrase. QnrB1 binds to the GyrB protein and stimulates ATPase activity of the isolated N-terminal ATPase domain of GyrB (GyrB43). We probed the QnrB1 binding site using site-specific incorporation of a photoreactive amino acid and mapped the crosslinks to the GyrB43 protein. We propose a model in which QnrB1 binding allosterically promotes dissociation of the fluoroquinolone molecule from the cleavage complex. 相似文献
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