scholarly journals The EGPs: the eclosion hormone and cyclic GMP-regulated phosphoproteins. II. Regulation of appearance by the steroid hormone 20- hydroxyecdysone in Manduca sexta

1988 ◽  
Vol 8 (4) ◽  
pp. 1338-1345 ◽  
Author(s):  
DB Morton ◽  
JW Truman
Keyword(s):  
Manduca Sexta ◽  
Cyclic Gmp ◽  
Steroid Hormone ◽  
Eclosion Hormone

The Larval Eclosion Hormone Neurones in Manduca Sexta: Identification of the Brain-Proctodeal Neurosecretory System

1989 ◽  
Vol 147 (1) ◽  
pp. 457-470 ◽  
Author(s):  
JAMES W. TRUMAN ◽  
PHILIP F. COPENHAVER
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Nerve Cord ◽  
Release Site ◽  
Neurosecretory System ◽  
Nerve Activity ◽  
Eclosion Hormone ◽  
The Central Nervous System ◽  
The Brain

Larval and pupal ecdyses of the moth Manduca sexta are triggered by eclosion hormone (EH) released from the ventral nervous system. The major store of EH activity in the latter resides in the proctodeal nerves that extend along the larval hindgut. At pupal ecdysis, the proctodeal nerves show a 90% depletion of stored activity, suggesting that they are the major release site for the circulating EH that causes ecdysis. Surgical experiments involving the transection of the nerve cord or removal of parts of the brain showed that the proctodeal nerve activity originates from the brain. Retrograde and anterograde cobalt fills and immunocytochemistry using antibodies against EH revealed two pairs of neurons that reside in the ventromedial region of the brain and whose axons travel ipsilaterally along the length of the central nervous system (CNS) and project into the proctodeal nerve, where they show varicose release sites. These neurons constitute a novel neuroendocrine pathway in insects which appears to be dedicated solely to the release of EH.

Ecdysteroids regulate the release and action of eclosion hormone in the tobacco hornworm, Manduca sexta (L.)

1983 ◽  
Vol 29 (12) ◽  
pp. 895-900 ◽  
Author(s):  
James W. Truman ◽  
Dorothy B. Rountree ◽  
Shirley E. Reiss ◽  
Lawrence M. Schwartz
Keyword(s):  
Manduca Sexta ◽  
Tobacco Hornworm ◽  
Eclosion Hormone

NADPH diaphorase activity in the antennae of the hawkmoth Manduca sexta

1996 ◽  
Vol 199 (5) ◽  
pp. 1063-1072 ◽  
Author(s):  
M Stengl ◽  
R Zintl
Keyword(s):  
Nitric Oxide ◽  
Manduca Sexta ◽  
Cyclic Gmp ◽  
Guanylyl Cyclase ◽  
Pupal Stage ◽  
Histochemical Staining ◽  
Nadph Diaphorase ◽  
Positive Staining ◽  
Receptor Cells ◽  
Diaphorase Activity

Biochemical and physiological studies suggested that increases in the levels of cyclic GMP in insect antennal receptor cells play a role in olfactory adaptation. As inositol-trisphosphate-dependent Ca2+ influx appears to precede the increase in intracellular cyclic GMP levels, it was hypothesized that a Ca2+-dependent mechanism might stimulate the guanylyl cyclase. The present study used histochemical staining for NADPH diaphorase to examine whether antennal receptor neurones of male Manduca sexta could contain nitric oxide synthase. This Ca2+/calmodulin-dependent enzyme is a prerequisite for nitric-oxide-dependent stimulation of guanylyl cyclase and possesses NADPH diaphorase activity. It was found that a subpopulation of olfactory receptor neurones as well as mechano-, thermo- and hygroreceptors on the moth antenna are NADPH-diaphorase-positive. Staining was also seen in non-neuronal cells. In the developing antenna, the NADPH-diaphorase-dependent staining was first observed at pupal stage 13-14, at approximately the same time as the antennal receptor neurones became physiologically active. The number and location of stained receptor cells was highly variable, and significantly more pheromone-sensitive sensilla were NADPH-diaphorase-positive in pheromone-stimulated antennae. This suggests that the enzyme is transiently activated by pheromone rather than being continuously active.

Control of Cuticle Extensibility in the Wings of Adult Manduca At the Time of Eclosion: Effects of Eclosion Hormone and Bursicon

1977 ◽  
Vol 70 (1) ◽  
pp. 27-39
Author(s):  
STUART E. REYNOLDS
Keyword(s):  
Manduca Sexta ◽  
Nerve Cord ◽  
Gel Filtration ◽  
Corpora Allata ◽  
Partial Purification ◽  
Active Principle ◽  
Eclosion Hormone ◽  
Highly Sensitive ◽  
The Brain ◽  
Pharate Adult

The wings of pharate adult tobacco hornworm moths, Manduca sexta, are relatively inextensible until 3 or 4 h before emergence from the pupal case. At this time the wing cuticle becomes plasticized, so that by the time of eclosion, the wings are readily extensible. This change in the mechanical properties of the wing cuticle is shown to be under the control of a factor from the head. This factor is present in the corpora cardiaca/corpora allata complex, and in the protocerebrum of the brain, being released into the blood prior to eclosion. It is able to act directly on isolated wings. The active principle was found to be indistinguishable in a number of ways from the hormone which triggers emergence from the pupal case, the eclosion hormone. Partial purification of the eclosion hormone failed to separate activity causing eclosion from activity causing wing cuticle plasticization. It is concluded that the same hormone is probably responsible for both effects. The cuticle plasticizing activity of the eclosion hormone forms the basis for a new, highly sensitive bioassay. Another factor, distinct from the eclosion hormone, is able to cause wing cuticle plasticization. This factor is found in the abdominal nerve cord, and is only released into the blood after eclosion has occurred. It is probably identical with the tanning hormone, bursicon, which is released at this time. The factor in the nerve cord which causes cuticle plasticization is indistinguishable from bursicon in a number of ways, including partial purification by gel filtration. Bursicon evidently causes a further increase in wing cuticle extensibility after eclosion, at the time of wing inflation.

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