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Inoculation of Wych elm (Ulmus glabra) with the fungi Ceratocystis ulmi, Chrondrostereum purpureum and Coriolus versicolor induced the formation of a series of antifungal cadinane-type sesquiterpenes. 相似文献
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Human ferrochelatase (E.C. 4.99.1.1) is a homodimeric (86 kDa) mitochondrial membrane-associated enzyme that catalyzes the insertion of ferrous iron into protoporphyrin to form heme. We have determined the 2.0 A structure from the single wavelength iron anomalous scattering signal. The enzyme contains two NO-sensitive and uniquely coordinated [2Fe-2S] clusters. Its membrane association is mediated in part by a 12-residue hydrophobic lip that also forms the entrance to the active site pocket. The positioning of highly conserved residues in the active site in conjunction with previous biochemical studies support a catalytic model that may have significance in explaining the enzymatic defects that lead to the human inherited disease erythropoietic protoporphyria. 相似文献
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Williamson Jennifer L. Tye Andrew Lapworth Dan J. Monteith Don Sanders Richard Mayor Daniel J. Barry Chris Bowes Mike Bowes Michael Burden Annette Callaghan Nathan Farr Gareth Felgate Stacey Fitch Alice Gibb Stuart Gilbert Pete Hargreaves Geoff Keenan Patrick Kitidis Vassilis Juergens Monika Martin Adrian Mounteney Ian Nightingale Philip D. Pereira M. Gloria Olszewska Justyna Pickard Amy Rees Andrew P. Spears Bryan Stinchcombe Mark White Debbie Williams Peter Worrall Fred Evans Chris 《Biogeochemistry》2022,160(3):423-424
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Insects modify their responses to stimuli through experience of associating those stimuli with events important for survival (e.g., food, mates, threats). There are several behavioral mechanisms through which an insect learns salient associations and relates them to these events. It is important to understand this behavioral plasticity for programs aimed toward assisting insects that are beneficial for agriculture. This understanding can also be used for discovering solutions to biomedical and agricultural problems created by insects that act as disease vectors and pests. The Proboscis Extension Response (PER) conditioning protocol was developed for honey bees (Apis mellifera) over 50 years ago to study how they perceive and learn about floral odors, which signal the nectar and pollen resources a colony needs for survival. The PER procedure provides a robust and easy-to-employ framework for studying several different ecologically relevant mechanisms of behavioral plasticity. It is easily adaptable for use with several other insect species and other behavioral reflexes. These protocols can be readily employed in conjunction with various means for monitoring neural activity in the CNS via electrophysiology or bioimaging, or for manipulating targeted neuromodulatory pathways. It is a robust assay for rapidly detecting sub-lethal effects on behavior caused by environmental stressors, toxins or pesticides.We show how the PER protocol is straightforward to implement using two procedures. One is suitable as a laboratory exercise for students or for quick assays of the effect of an experimental treatment. The other provides more thorough control of variables, which is important for studies of behavioral conditioning. We show how several measures for the behavioral response ranging from binary yes/no to more continuous variable like latency and duration of proboscis extension can be used to test hypotheses. And, we discuss some pitfalls that researchers commonly encounter when they use the procedure for the first time. 相似文献