Carotenoid Biogenesis in the Stick Insect, Carausius morosus, during a Larval Instar

1982 ◽  
Vol 37 (1-2) ◽  
pp. 13-18 ◽  
Author(s):  
Hartmut Kayser
Keyword(s):  
Larval Instar ◽  
Stick Insect ◽  
Carausius Morosus ◽  
Stick Insects ◽  
Microbial Symbionts ◽  
Β Carotene

[14C]β-Carotene was fed to juvenile stick insects, Carausius morosus, of the fifth instar. Radioactivity was incorporated into 2-hydroxy-, 2-oxo-, and 3,4-didehydro-2-oxo-carotenoids of the β,β-type. These transformations are due to the insect’s own capacity; any contribution by microbial symbionts can be ruled out. A study on the labelling kinetics clearly shows that the biogenesis of hydroxy- and oxo-carotenoids is correlated to a decrease in the carotene precursor, but only up to mid instar. Thereafter, oxidation of the carotene is very low but the transformations of its metabolites continue as before. Predominantly β,β-carotene-2,2'-diol is dehydrogenated to 3,4,3',4'-tetradehydro-β,β-carotene-2,2'-dione via two hydroxyketones. This discontinuous utilization of β-carotene could be due to a stop at mid instar either in the oxidation or in the absorption in the gut of this precursor.

Processing of Sensory Input from the Femoral Chordotonal Organ by Spiking Interneurones of Stick Insects

1989 ◽  
Vol 144 (1) ◽  
pp. 81-111 ◽  
Author(s):  
ANSGAR BÜSCHGES
Keyword(s):  
Time Course ◽  
Sensory Input ◽  
Stick Insect ◽  
Chordotonal Organ ◽  
Carausius Morosus ◽  
Median Part ◽  
Stick Insects ◽  
Position Sensitivity ◽  
The Right ◽  
Stimulation Of

The femoral chordotonal organ (ChO) of the right middle leg of the inactive stick insect Carausius morosus was stimulated by applying movements having a ramp-like time course, while recordings were made from local and interganglionic interneurones in the anterior ventral median part of the ganglion. Position, velocity and acceleration of the movements were varied independently and the interneurones were categorized on the basis of their responses to the changes in these parameters. Position-sensitivity was always accompanied by responses to velocity and/or acceleration. Velocity-sensitive responses were excitatory or inhibitory and were produced by elongation or relaxation, or by both. In some cases, velocity-sensitive neurones were also affected by position and acceleration. Acceleration responses were always excitatory and were often found in neurones that showed no effects of velocity or position. It is inferred that sensory input from different receptors in the ChO is processed by single interneurones. No interneurone in the recording region was found to be directly involved in the resistance reflex of the extensor tibiae motoneurones, elicited by stimulation of the ChO.

scholarly journals Control of Stepping Velocity in the Stick Insect Carausius morosus

2009 ◽  
Vol 102 (2) ◽  
pp. 1180-1192 ◽  
Author(s):  
Matthias Gruhn ◽  
Géraldine von Uckermann ◽  
Sandra Westmark ◽  
Anne Wosnitza ◽  
Ansgar Büschges ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Walking Speed ◽  
Stick Insect ◽  
Behavioral Experiments ◽  
General Increase ◽  
Carausius Morosus ◽  
Mechanical Coupling ◽  
Stick Insects ◽  
Motoneuron Activity ◽  
Slippery Surface

We performed electrophysiological and behavioral experiments in single-leg preparations and intact animals of the stick insect Carausius morosus to understand mechanisms underlying the control of walking speed. At the level of the single leg, we found no significant correlation between stepping velocity and spike frequency of motor neurons (MNs) other than the previously shown modification in flexor (stance) MN activity. However, pauses between stance and swing motoneuron activity at the transition from stance to swing phase and stepping velocity are correlated. Pauses become shorter with increasing speed and completely disappear during fast stepping sequences. By means of extra- and intracellular recordings in single-leg stick insect preparations we found no systematic relationship between the velocity of a stepping front leg and the motoneuronal activity in the ipsi- or contralateral mesothoracic protractor and retractor, as well as flexor and extensor MNs. The observations on the lack of coordination of stepping velocity between legs in single-leg preparations were confirmed in behavioral experiments with intact stick insects tethered above a slippery surface, thereby effectively removing mechanical coupling through the ground. In this situation, there were again no systematic correlations between the stepping velocities of different legs, despite the finding that an increase in stepping velocity in a single front leg is correlated with a general increase in nerve activity in all connectives between the subesophageal and all thoracic ganglia. However, when the tethered animal increased walking speed due to a short tactile stimulus, provoking an escape-like response, stepping velocities of ipsilateral legs were found to be correlated for several steps. These results indicate that there is no permanent coordination of stepping velocities between legs, but that such coordination can be activated under certain circumstances.

Identification of β,β-Caroten-2-ol and β,β-Carotene-2,2′-diol in the Stick Insect, Carausius morosus Br.; a Reinvestigation Study

1976 ◽  
Vol 31 (11-12) ◽  
pp. 646-651 ◽  
Author(s):  
Hartmut Kayser
Keyword(s):  
Fatty Acids ◽  
Acid Solution ◽  
Mass Spectra ◽  
Stick Insect ◽  
Carausius Morosus ◽  
Chemical Behaviour ◽  
Β Carotene

Abstract Two major carotenoids of the stick insect were reinvestigated and shown to be β,β-caroten-2-ol and β,β-carotene-2,2′-diol and not isocryptoxanthin (β,β-caroten-4-ol) and isozeaxanthin (β,β-carotene-4,4′-diol). Both pigments are esterified with fatty acids. The identification is based on co-chromatography with authentic 2-, 3-and 4-isomers of the mono-and dihydroxy pigment, mass spectra, and chemical behaviour. In acid solution β-β-carotene-2,2′-diol is specifically dehydro­ genated and rearranged to ketones with retro structures in analogy to the reaction of β,β-caroten-2-ol as recently reported. The final product of the diol is 4,5-dihydro-4,5′-retro-β,β-carotene-2,2′-dione. This is the first demonstration of β,β-carotene-2,2′-diol in an animal.

The effects of ionic lanthanum and hypertonic physiological salines on the nervous systems of larval and adult stick insects

1975 ◽  
Vol 18 (2) ◽  
pp. 271-286
Author(s):  
R.A. Leslie
Keyword(s):  
Nervous System ◽  
Diffusion Barrier ◽  
Physiological Saline ◽  
Stick Insect ◽  
Nervous Systems ◽  
Carausius Morosus ◽  
Nerve Sheath ◽  
Ionic Lanthanum ◽  
Stick Insects ◽  
Peripheral Nervous Systems

The effects of the electron-opaque tracer ionic lanthanum in various concentrations and of hyperosmotic physiological salines on the nervous system of the stick insect, Carausius morosus, have been studied. Examination of the experimentally treated tissues revealed that the diffusion barrier to the exogenous tracer was maintained in all cases in the adult central and peripheral nervous systems, but not in the hatchling. When hatchling nervous tissues were incubated in 50 mM ionic lanthanum in phyerosmotic physiological saline, the tracer readily infiltrated all the extracellular spaces between axons and glia of all components of the nervous system examined. No difference was noted in this regard between fed and unfed hatchlings, Further, in all cases examined of adults and hatchlings, lanthanum readily surrounded those neurosecretory axons which are found in the neutral lamella, or extracellular nerve sheath, of the insect. The possible meanings of these variations in hatchling and adult nervous systems and in the accessibility of different elements of the nervous system to exogenous ionic lanthanum are discussed.

Carotenoids in the Stick Insect, Ectatosoma tiaratum Isolation of β,Ɛ-Caroten-2-ol and β,Ɛ-Caroten-2-one

1981 ◽  
Vol 36 (9-10) ◽  
pp. 755-764 ◽  
Author(s):  
Hartmut Kayser
Keyword(s):  
Stick Insect ◽  
Chemical Methods ◽  
Specific Product ◽  
First Report ◽  
Stick Insects ◽  
Β Carotene

Abstract 2-Oxo-carotenoids, 2-Hydroxy-carotenoids, [uC]/β-Carotene, Metabolism, Stick Insects The carotenoids of the stick insect, Ectatosoma tiaratum, were studied by spectroscopic and chemical methods. The β,β-type pigments are β,β-carotene, β,β-caroten-2-one, β,β-caroten-2-ol, β,β-carotene-2,2'-dione, 2'-hydroxy-β,β-caroten-2-one, β,ε-carotene-2,2'-diol, 3,4-didehydro-β,β-carotene-2,2'-dione, 2'-hydroxy-3,4-didehydro-β,β-caroten-2-one, and 3,4,3',4'-tetradehydro-β,β-carotene-2,2'-dione. In addition, the following β,ε-type pigments were identified: β,ε-carotene, β,e-caroten-2-ol, and β,e-caroten-2-one. This is the first report on the occurrence of β,e-caroten-2-ol in an animal and of β,ε-caroten-2-one in nature at all. On treatment with BF3 in chloroform β,ε-caroten-2-ol is dehydrated to a specific product with the proposed structure of 2,3-didehydro-4,7'-retro-β, e-carotene.The biogenesis of the β,β-type carotenoids from β,ε-carotene is demonstrated by feeding [14C]β-carotene to the insects. Radiolabel was incorporated into all major metabolites of this type. The metabolism of carotenoids in stick insects is discussed applying the "half-molecule sub­ strate" hypothesis to the enzymic transformations of the pigments.

Intersegmental Coordination of Walking Movements in Stick Insects

2005 ◽  
Vol 93 (3) ◽  
pp. 1255-1265 ◽  
Author(s):  
Björn Ch. Ludwar ◽  
Marie L. Göritz ◽  
Joachim Schmidt
Keyword(s):  
Motor Pattern ◽  
Central Pattern Generators ◽  
Stick Insect ◽  
Neural Mechanisms ◽  
Chordotonal Organ ◽  
Adjacent Segment ◽  
Body Segments ◽  
Stick Insects ◽  
Pattern Generators ◽  
Leg Movements

Locomotion requires the coordination of movements across body segments, which in walking animals is expressed as gaits. We studied the underlying neural mechanisms of this coordination in a semi-intact walking preparation of the stick insect Carausius morosus. During walking of a single front leg on a treadmill, leg motoneuron (MN) activity tonically increased and became rhythmically modulated in the ipsilateral deafferented and deefferented mesothoracic (middle leg) ganglion. The pattern of modulation was correlated with the front leg cycle and specific for a given MN pool, although it was not consistent with functional leg movements for all MN pools. In an isolated preparation of a pair of ganglia, where one ganglion was made rhythmically active by application of pilocarpine, we found no evidence for coupling between segmental central pattern generators (CPGs) that could account for the modulation of MN activity observed in the semi-intact walking preparation. However, a third preparation provided evidence that signals from the front leg's femoral chordotonal organ (fCO) influenced activity of ipsilateral MNs in the adjacent mesothoracic ganglion. These intersegmental signals could be partially responsible for the observed MN activity modulation during front leg walking. While afferent signals from a single walking front leg modulate the activity of MNs in the adjacent segment, additional afferent signals, local or from contralateral or posterior legs, might be necessary to produce the functional motor pattern observed in freely walking animals.

scholarly journals Peripheral Influences on the Movement of the Legs in a Walking Insect Carausius Morosus

1982 ◽  
Vol 101 (1) ◽  
pp. 161-170 ◽  
Author(s):  
H. CRUSE ◽  
S. EPSTEIN
Keyword(s):  
Glass Plate ◽  
The Other ◽  
Extreme Position ◽  
Carausius Morosus ◽  
Stick Insects

Anterior extreme position (AEP) and posterior extreme position (PEP)of the legs of stick insects were measured during walking on a tread wheelor on a slippery glass plate. In several experiments, either protraction or retraction of a middle or hind leg was interrupted. The AEP of ot her legs was independent of a protraction interruption but PEP was displaced backward in the leg anterior to the interrupted leg. When a leg was standing on a fixed platform (interruption of retraction) no changes were found in AEP and PEP for the other legs but if the platform was slowly moved, PEP of leg on the platform was moved forward. These results disagree with several publishedhypotheses. The results suggest the hypothesis of a position-dependentthreshold value for protraction which is modulated by co-ordinating influencesfrom other legs. Note:

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