scholarly journals Sensorimotor pathway controlling stopping behavior during chemotaxis in the Drosophila melanogaster larva

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Ibrahim Tastekin ◽  
Avinash Khandelwal ◽  
David Tadres ◽  
Nico D Fessner ◽  
James W Truman ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drosophila Melanogaster ◽  
Olfactory System ◽  
Action Selection ◽  
Pivotal Role ◽  
Motor Circuit ◽  
Mechanistic Analysis ◽  
Main Pathway ◽  
Peripheral Olfactory System ◽  
Artificial Activation

Sensory navigation results from coordinated transitions between distinct behavioral programs. During chemotaxis in the Drosophila melanogaster larva, the detection of positive odor gradients extends runs while negative gradients promote stops and turns. This algorithm represents a foundation for the control of sensory navigation across phyla. In the present work, we identified an olfactory descending neuron, PDM-DN, which plays a pivotal role in the organization of stops and turns in response to the detection of graded changes in odor concentrations. Artificial activation of this descending neuron induces deterministic stops followed by the initiation of turning maneuvers through head casts. Using electron microscopy, we reconstructed the main pathway that connects the PDM-DN neuron to the peripheral olfactory system and to the pre-motor circuit responsible for the actuation of forward peristalsis. Our results set the stage for a detailed mechanistic analysis of the sensorimotor conversion of graded olfactory inputs into action selection to perform goal-oriented navigation.

scholarly journals Defective signaling through plexin-A1 compromises the development of the peripheral olfactory system and neuroendocrine reproductive axis in mice

2017 ◽  
Vol 26 (11) ◽  
pp. 2006-2017 ◽  
Author(s):  
Séverine Marcos ◽  
Carine Monnier ◽  
Xavier Rovira ◽  
Corinne Fouveaut ◽  
Nelly Pitteloud ◽  
...  
Keyword(s):  
Olfactory System ◽  
Reproductive Axis ◽  
Peripheral Olfactory System

scholarly journals Structural anomalies of the peripheral olfactory system in psychosis high-risk subjects

2018 ◽  
Vol 195 ◽  
pp. 197-205 ◽  
Author(s):  
Bruce I. Turetsky ◽  
Paul J. Moberg ◽  
Megan Quarmley ◽  
Erich Dress ◽  
Monica E. Calkins ◽  
...  
Keyword(s):  
High Risk ◽  
Olfactory System ◽  
Peripheral Olfactory System ◽  
Structural Anomalies

scholarly journals Endothelium-derived hyperpolarizing factor in preeclampsia: heterogeneous contribution, mechanisms, and morphological prerequisites

2008 ◽  
Vol 294 (2) ◽  
pp. R510-R519 ◽  
Author(s):  
Leanid Luksha ◽  
Henry Nisell ◽  
Natallia Luksha ◽  
Marius Kublickas ◽  
Kjell Hultenby ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Subcutaneous Fat ◽  
Normal Pregnancy ◽  
Transmission Electron ◽  
Main Pathway ◽  
Before And After ◽  
Group 2 ◽  
Cytochrome P 450 ◽  
Group 1

We hypothesized that in preeclampsia (PE), contribution of endothelium-derived hyperpolarizing factor (EDHF) and the mechanism/s of its action differ from that in normal pregnancy (NP). We aimed to assess endothelial function and morphology in arteries from NP and PE with particular focus on EDHF. Arteries (≈200 μm) were dissected from subcutaneous fat biopsies obtained from women undergoing cesarean section. With the use of wire myography, responses to the endothelium-dependent agonist bradykinin (BK) were determined before and after inhibition of pathways relevant to EDHF activity. The overall responses to BK in arteries from PE ( n = 13) and NP ( n = 17) were similar. However, in PE, EDHF-mediated relaxation was reduced ( P < 0.05). All women within the PE group were divided into two subgroups: with more ( group 1) or less ( group 2) than 50% reduction of EDHF-typed responses after 18-α-glycyrrhetinic acid (an inhibitor of myoendothelial gap junctions, MEGJs). The division showed that 1) MEGJs are principally involved when the EDHF contribution is reduced; and 2) when the EDHF contribution is similar to that in NP, the H2O2 and/or cytochrome P-450 epoxygenase products of arachidonic acid (AA), along with MEGJs, confer EDHF-mediated relaxation. In contrast, MEGJs were the main pathway for EDHF in NP. The abundant presence of MEGJs in arteries from NP but deficiency of them in PE was observed using transmission electron microscopy. We conclude that PE is associated with heterogeneous contribution of EDHF, and the mechanism behind EDHF-typed responses is mediated either by MEGJs alone or in combination with H2O2 or cytochrome P-450 epoxygenase metabolites of AA.

scholarly journals Cell Division by Longitudinal Scission in the Insect EndosymbiontSpiroplasma poulsonii

mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Elodie Ramond ◽  
Catherine Maclachlan ◽  
Stéphanie Clerc-Rosset ◽  
Graham W. Knott ◽  
Bruno Lemaitre
Keyword(s):  
Electron Microscopy ◽  
Drosophila Melanogaster ◽  
Cell Division ◽  
Longitudinal Mode ◽  
Fruit Fly ◽  
Endosymbiotic Bacterium ◽  
Infected Female ◽  
Immunogold Staining ◽  
Ftsz Protein ◽  
Mode Of Life

ABSTRACTSpiroplasmabacteria are highly motile bacteria with no cell wall and a helical morphology. This clade includes many vertically transmitted insect endosymbionts, includingSpiroplasma poulsonii, a natural endosymbiont ofDrosophila melanogaster.S. poulsoniibacteria are mainly found in the hemolymph of infected female flies and exhibit efficient vertical transmission from mother to offspring. As is the case for many facultative endosymbionts,S. poulsoniican manipulate the reproduction of its host; in particular,S. poulsoniiinduces male killing inDrosophila melanogaster. Here, we analyze the morphology ofS. poulsoniiobtained from the hemolymph of infectedDrosophila. This endosymbiont was not only found as long helical filaments, as previously described, but was also found in a Y-shaped form. The use of electron microscopy, immunogold staining of the FtsZ protein, and antibiotic treatment unambiguously linked the Y shape ofS. poulsoniito cell division. Observation of the Y shape in anotherSpiroplasma,S. citri, and anecdotic observations from the literature suggest that cell division by longitudinal scission might be prevalent in theSpiroplasmaclade. Our study is the first to report the Y-shape mode of cell division in an endosymbiotic bacterium and addsSpiroplasmato the so far limited group of bacteria known to utilize this cell division mode.IMPORTANCEMost bacteria rely on binary fission, which involves elongation of the bacteria and DNA replication, followed by splitting into two parts. Examples of bacteria with a Y-shape longitudinal scission remain scarce. Here, we report thatSpiroplasma poulsonii, an endosymbiotic bacterium living inside the fruit flyDrosophila melanogaster, divide with the longitudinal mode of cell division. Observations of the Y shape in anotherSpiroplasma,S. citri, suggest that this mode of scission might be prevalent in theSpiroplasmaclade.Spiroplasmabacteria are wall-less bacteria with a distinctive helical shape, and these bacteria are always associated with arthropods, notably insects. Our study raises the hypothesis that this mode of cell division by longitudinal scission could be linked to the symbiotic mode of life of these bacteria.

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