scholarly journals Synaptogenesis in the giant-fibre system of Drosophila: interaction of the giant fibre and its major motorneuronal target

Development ◽  
2000 ◽  
Vol 127 (23) ◽  
pp. 5203-5212
Author(s):  
K. Jacobs ◽  
M.G. Todman ◽  
M.J. Allen ◽  
J.A. Davies ◽  
J.P. Bacon
Keyword(s):  
Fluorescent Protein ◽  
Lucifer Yellow ◽  
Active Form ◽  
Dye Coupling ◽  
Electrical Synapses ◽  
Giant Fibre ◽  
High Resolution Data ◽  
After Puparium Formation ◽  
Puparium Formation ◽  
Giant Fibre System

The tergotrochanteral (jump) motorneuron is a major synaptic target of the Giant Fibre in Drosophila. These two neurons are major components of the fly's Giant-Fibre escape system. Our previous work has described the development of the Giant Fibre in early metamorphosis and the involvement of the shaking-B locus in the formation of its electrical synapses. In the present study, we have investigated the development of the tergotrochanteral motorneuron and its electrical synapses by transforming Drosophila with a Gal4 fusion construct containing sequences largely upstream of, but including, the shaking-B(lethal) promoter. This construct drives reporter gene expression in the tergotrochanteral motorneuron and some other neurons. Expression of green fluorescent protein in the motorneuron allows visualization of its cell body and its subsequent intracellular staining with Lucifer Yellow. These preparations provide high-resolution data on motorneuron morphogenesis during the first half of pupal development. Dye-coupling reveals onset of gap-junction formation between the tergotrochanteral motorneuron and other neurons of the Giant-Fibre System. The medial dendrite of the tergotrochanteral motorneuron becomes dye-coupled to the peripheral synapsing interneurons between 28 and 32 hours after puparium formation. Dye-coupling between tergotrochanteral motorneuron and Giant Fibre is first seen at 42 hours after puparium formation. All dye coupling is abolished in a shaking-B(neural) mutant. To investigate any interactions between the Giant Fibre and the tergotroachanteral motorneuron, we arrested the growth of the motorneuron's medial neurite by targeted expression of a constitutively active form of Dcdc42. This results in the Giant Fibre remaining stranded at the midline, unable to make its characteristic bend. We conclude that Giant Fibre morphogenesis normally relies on fasciculation with its major motorneuronal target.

THE HISTOLOGY OF THE GIANT FIBRE SYSTEM IN THE ABDOMINAL VENTRAL NERVE CORD OF THE DESERT LOCUST

1970 ◽  
Vol 102 (9) ◽  
pp. 1163-1168 ◽  
Author(s):  
W. D. Seabrook
Keyword(s):  
Single Cell ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Schistocerca Gregaria ◽  
Desert Locust ◽  
Giant Fibre ◽  
Metathoracic Ganglion ◽  
Giant Fibres ◽  
Giant Fibre System

AbstractSchistocerca gregaria possess four neurones of giant fibre proportions within the abdominal ventral nerve cord. These fibres arise from single cell bodies in the terminal ganglionic mass and pass without interruption to the metathoracic ganglion. Fibres become reduced in diameter when passing through a ganglion. Branching of the giant fibres occurs in abdominal ganglia 6 and 7.

Neurofilament phosphorylation and axon diameter in the squid giant fibre system

Neuroscience ◽  
1999 ◽  
Vol 88 (1) ◽  
pp. 327-336 ◽  
Author(s):  
R Martin ◽  
R Door ◽  
A Ziegler ◽  
W Warchol ◽  
J Hahn ◽  
...  
Keyword(s):  
Axon Diameter ◽  
Giant Fibre ◽  
Neurofilament Phosphorylation ◽  
Giant Fibre System

scholarly journals The Segmental Giant Neurone of the Hermit Crab Eupagurus Bernhardus

1986 ◽  
Vol 125 (1) ◽  
pp. 245-269 ◽  
Author(s):  
W. J. Heitler ◽  
K. Fraser
Keyword(s):  
Cell Body ◽  
Hermit Crab ◽  
Small Cell ◽  
Electrical Synapse ◽  
Giant Fibre ◽  
Anatomy And Physiology ◽  
Motor Neurones ◽  
Evolutionary Paths ◽  
Contralateral Motor ◽  
Giant Fibre System

The anatomy and physiology of the segmental giant (SG) neurone of the fourth abdominal ganglion of the hermit crab is described. The SG has an apparently blindending axon in the first root and a small cell body in the anterior ipsilateral ventral quadrant of the ganglion. There is a large ipsilateral neuropile arborization with prominent dendrites lined up along the course of the ipsilateral giant fibre (GF). The SG receives 1:1 input from the ipsilateral GF via an electrical synapse which is usually rectifying. SG activation produces a large EPSP in all ipsilateral and some contralateral fast flexor excitor (FF) motor neurones. The major input to FFs resulting from GF activation appears to be mediated via the SG. It also produces a small EPSP in ipsilateral and contralateral motor giant neurones. The properties of the hermit crab SG are compared to those of the crayfish SG, and the implications of the SG for the possible evolutionary paths of the giant fibre system are discussed.

Paradoxical overexpression and translocation of connexin43 in homocysteine-treated endothelial cells

2002 ◽  
Vol 282 (6) ◽  
pp. H2124-H2133 ◽  
Author(s):  
Hong Li ◽  
Sergey Brodsky ◽  
Sindu Kumari ◽  
Virginijus Valiunas ◽  
Peter Brink ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Fluorescent Protein ◽  
Lucifer Yellow ◽  
Umbilical Vein ◽  
Expression Screening ◽  
Fluorescent Markers ◽  
Junctional Communication ◽  
Green Fluorescent ◽  
Umbilical Vein Endothelial Cells

Hyperhomocysteinemia is an established cause of defective vasorelaxation. Gene expression screening of human umbilical vein endothelial cells (HUVEC) treated with homocysteine (Hcy) revealed that connexin43 (Cx43) was upregulated. Expression of Cx43 was increased more than twofold in Hcy-treated HUVEC. Gap junctional communication (Lucifer yellow and whole cell patch clamp) was not enhanced in Hcy-treated HUVEC. HUVEC expressing chimeric Cx43-green fluorescent protein exhibited it at cell-cell contacts in control but showed redistribution to the intracellular compartment(s) in Hcy-treated cells. Confocal microscopy of HUVEC stained with anti-Cx43, mitochondrial, and endoplasmic reticulum fluorescent markers showed the localization of Cx43 to the plasma membrane of control cells and its colocalization with the mitochondrial marker in Hcy-treated HUVEC. Studies of isolated mitochondria confirmed overexpression of Cx43 in the mitochondria of Hcy-treated HUVEC. Microdissected renal interlobar arteries, which normally exhibit endothelium-derived hyperpolarizing factor-induced vasorelaxation, showed reduced nitric oxide synthase- and cyclooxygenase-independent vasorelaxation to acetylcholine after pretreatment with Hcy. In summary, Hcy-induced upregulation of Cx43 transcript and protein expression are associated with unaltered intercellular communication, redistribution of Cx43 in HUVEC, and reduced nitric oxide- and prostanoid-independent vascular responses to acetylcholine in Hcy-treated arteries.

scholarly journals Neuropeptides Exert Direct Effects on Rat Thymic Epithelial Cells in Culture

1998 ◽  
Vol 6 (1-2) ◽  
pp. 95-104 ◽  
Author(s):  
Gail M. Head ◽  
R. Mentlein ◽  
Birte Von Patay ◽  
J. E.G. Downing ◽  
Marion D. Kendall
Keyword(s):  
Epithelial Cells ◽  
Lucifer Yellow ◽  
Tritiated Thymidine ◽  
Single Cells ◽  
Thymic Epithelial Cells ◽  
Dye Coupling ◽  
Direct Effects ◽  
Adrenergic Agonist ◽  
Thymic Epithelium ◽  
Functional Aspects

To determine if major thymic neuropeptides and neurotransmitters can directly influence the functional activity of cultured rat thymic epithelium, neuropeptides and neurotransmitters were applied, and intercellular communication, proliferation, and thymulin secretion assessed. After injections of a mixture of lucifer yellow dextran (too large to pass gap junctions) and cascade blue (which does) into single cells, some neuropeptides decrease dye coupling: 0.1 mM GABA (P< 0.0001), 100 nM NPY (P< 0.0001), 100 nM VIP (P< 0.001), 100 nM CGRP (P< 0.001), 100 nM SP (P< 0.01), and 0.1 mM histamine (P< 0.01), whereas 0.1 mM 5-HT, mM acetylcholine, and 1μM isoproterenol (β-adrenergic agonist) had no effect. Proliferation (incorporation of tritiated thymidine) was increased by CGRP (P= 0.004) and histamine (P< 0.02), but decreased by isoproterenol (P= 0.002), 5-HT (P= 0.003), and acetylcholine (P< 0.05). The percentage of multinucleate cells was decreased after isoproterenol (2.5%), and increased after 5-HT (21.3%), GABA (15%), and histamine (15.1%). Compared to controls, thymulin in the supernatant was decreased after challenge with acetylcholine (52%), isoproterenol (71%), 5-HT (73%), and histamine (84%). This study demonstrates direct effects of neuropeptides and neurotransmitters on functional aspects of cultured thymic epithelial cells.

Relationship between Na+ current expression and cell-cell coupling in astrocytes cultured from rat hippocampus

1991 ◽  
Vol 65 (4) ◽  
pp. 989-1002 ◽  
Author(s):  
H. Sontheimer ◽  
S. G. Waxman ◽  
B. R. Ransom
Keyword(s):  
Lucifer Yellow ◽  
Na Channel ◽  
Dye Coupling ◽  
Cell Coupling ◽  
Na Current ◽  
Na Currents ◽  
Coupled Cells ◽  
Hippocampal Astrocytes ◽  
Cell Cell

1. Cell-cell coupling between hippocampal astrocytes in culture was studied by following the intracellular spread of the low molecular weight fluorescent dye Lucifer yellow (LY). Dye coupling appeared as early as 24 h after plating, at which time approximately 20% of all astrocytes that physically contacted neighboring cells showed dye coupling. 2. The percentage of coupled cells increased with time in culture and peaked after 10 days in vitro (DIV) when approximately 50% of astrocytes showed coupling. Further time in culture, up to 20 DIV, did not increase the percentage of coupled cells. Thus, coupled and noncoupled astrocytes coexist in hippocampal cultures in approximately equal numbers. 3. Na+ currents were expressed in a subpopulation of hippocampal astrocytes and changed characteristics during in vitro development. A "neuronal type" of Na+ current, so called because of an h alpha curve that had a midpoint near -60 mV, was observed within the first 5 days post-plating. A "glial type" of Na+ current, characterized by a -25 mV shift in its h alpha curve, was only expressed after 6 days in culture. 4. Na+ current expression was restricted to hippocampal astrocytes that did not exhibit dye coupling; astrocytes that exhibited dye coupling (n = 39) did not show measurable Na+ currents. 5. The failure to see Na+ currents in coupled astrocytes cannot be explained by insufficient space-clamp since astrocytes acutely uncoupled with octanol (10 microM) did not reveal Na+ current expression. Control experiments showed that low concentrations of octanol (i.e., 10-100 microM) did not block Na+ currents; blockage of Na+ currents by octanol was only observed at high concentrations (e.g., 50-fold the concentration used for uncoupling). These observations support the idea that Na(+)-channel expression was restricted to noncoupled astrocytes. 6. The time courses for the development of cell coupling and Na+ current expression appeared to be inversely correlated and suggested a gradual increase in cell coupling in concert with a loss in Na+ current expression with time in culture.

scholarly journals Aliivibrio wodanis as a production host: development of genetic tools for expression of cold-active enzymes

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Jenny Johansson Söderberg ◽  
Miriam Grgic ◽  
Erik Hjerde ◽  
Peik Haugen
Keyword(s):  
Low Temperature ◽  
Protein Production ◽  
Fluorescent Protein ◽  
Active Form ◽  
Rhodococcus Erythropolis ◽  
Expression Systems ◽  
Cold Adapted ◽  
Genetic Tools ◽  
Cold Active Enzymes ◽  
Cold Active

Abstract Background Heterologous production of cold-adapted proteins currently represents one of the greatest bottlenecks in the ongoing bioprospecting efforts to find new enzymes from low-temperature environments, such as, the polar oceans that represent essentially untapped resources in this respect. In mesophilic expression hosts such as Escherichia coli, cold-adapted enzymes often form inactive aggregates. Therefore it is necessary to develop new low-temperature expression systems, including identification of new host organisms and complementary genetic tools. Psychrophilic bacteria, including Pseudoalteromonas haloplanktis, Shewanella and Rhodococcus erythropolis have all been explored as candidates for such applications. However to date none of these have found widespread use as efficient expression systems, or are commercially available. In the present work we explored the use of the sub-Arctic bacterium Aliivibrio wodanis as a potential host for heterologous expression of cold-active enzymes. Results We tested 12 bacterial strains, as well as available vectors, promoters and reporter systems. We used RNA-sequencing to determine the most highly expressed genes and their intrinsic promoters in A. wodanis. In addition we examined a novel 5′-fusion to stimulate protein production and solubility. Finally we tested production of a set of “difficult-to-produce” enzymes originating from various bacteria and one Archaea. Our results show that cold-adapted enzymes can be produced in soluble and active form, even in cases when protein production failed in E. coli due to the formation of inclusion bodies. Moreover, we identified a 60-bp/20-aa fragment from the 5′-end of the AW0309160_00174 gene that stimulates expression of Green Fluorescent Protein and improves production of cold-active enzymes when used as a 5′-fusion. A 25-aa peptide from the same protein enhanced secretion of a 25-aa-sfGFP fusion. Conclusions Our results indicate the use of A. wodanis and associated genetic tools for low-temperature protein production and indicate that A. wodanis represents an interesting platform for further development of a protein production system that can promote further cold-enzyme discoveries.

Reversible carbon dioxide-induced inhibition of dye coupling in Necturus gallbladder

1983 ◽  
Vol 244 (5) ◽  
pp. C419-C421 ◽  
Author(s):  
J. A. Jarrell
Keyword(s):  
Carbon Dioxide ◽  
Lucifer Yellow ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Dye Coupling ◽  
Gallbladder Epithelium ◽  
Intracellular Injection ◽  
Necturus Gallbladder ◽  
High Concentrations

The cells of Necturus gallbladder epithelium are electrically coupled. This work used intracellular injection of the fluorescent dye Lucifer yellow to demonstrate that these cells are also dye coupled and that this coupling is rapidly and reversibly inhibited by high concentrations of carbon dioxide. Dye coupling is also inhibited by the calcium ionophore A23187.

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