Noelle Granger - Academia.edu (original) (raw)
Papers by Noelle Granger
General and Comparative Endocrinology, 1987
A previous study of the role of 20-hydroxyecdysone in the regulation of juvenile hormone (JH) bio... more A previous study of the role of 20-hydroxyecdysone in the regulation of juvenile hormone (JH) biosynthesis during pupal commitment in the last (fifth, V) larval instar of Manduca sexta revealed that the increase in the hemolymph edysteroid titer that elicits commitment also stimulates the corpora allata (CA) to synthesize JHs I and III and/or their acids. This stimulation is exerted indirectly via the brain-corpora cardiaca and results in the postcommitment increase in the JH titer that is important for the molt to a pupa. The possibility that a similar form of interendocrine regulation of JH biosynthesis by 20-hydroxyecdysone is involved in the control of larval molting in Manduca was investigated for the molt from the fourth (IV) to the V larval instar. During the IV instar, the increase in the hemolymph ecdysteroid titer and the capacity of the CA to synthesize JHs I and III in vitro correlated temporally in a manner suggestive of CA regulation by 20-hydroxyecdysone. With an in vitro approach, physiological concentrations of 20-hydroxyecdysone (greater than or equal to 1 microgram ml-1 hemolymph) were shown to have a dose-dependent trophic effect on CA activity, specifically stimulating JH I synthesis. Since neither basally active nor stimulated CA contained significant amounts of JH I, it appears that 20-hydroxyecdysone acts at the level of biosynthesis rather than at the level of release. The specificity of 20-hydroxyecdysone stimulation of JH I synthesis was demonstrated by the inability of the biologically inactive ecdysteroids 22-isoecdysone and 5 alpha-ecdysone to activate the glands.(ABSTRACT TRUNCATED AT 250 WORDS)
Journal of Insect Physiology, 1994
A white mutant of the tobacco hornworm, Manduca sexta, was discovered among wild-type, blue-green... more A white mutant of the tobacco hornworm, Manduca sexta, was discovered among wild-type, blue-green larvae in a laboratory colony routinely supplemented with field-collected insects. The mutant is pinkish-white when reared on artificial diet and maintains this coloration from egg hatch through pupation. Spectral analyses showed that the blue chromophore, biliverdin, which is present in the integument and plasma of wild-type, diet and tobacco-reared larvae, was lacking in the white mutant reared on the same diets. Insecticyanin levels determined by radial immunodiffusion in the integument and plasma of the white mutant were half that of normal blue-green larvae. The topical application of increasing amounts of the juvenoid, 2-(l-methyl-2-(4-phenoxyphenoxy)ethoxy)pyridine, to wildtype, day 1 first stadium larvae of M. sexta was positively correlated with the intensity of white coloration, which first appeared in newly molted second instars and was retained until pupation. White-mutant larvae developed slower and were slightly larger than wild-type larvae. The corpora allata from last stadium, day 0 larvae of the white mutant demonstrated a higher rate of JH/JH acid biosynthesis and the hemolymph had a higher titer of JH than the wild type of the same age. These studies suggested that JH may play a role in the regulation of the white phenotype. No differences were noted in the level of JH esterase activity between the two strains during the last stadium. Biliverdin Carotenoid Color Insecticyanin Juvenile hormone Juvenile hormone biosynthesis Juvenile hormone esterase Manduca sexta Tobacco hornworm
Archives of Insect Biochemistry and Physiology, 1995
An assay was developed with which to study basic characteristics of an adenylyl cyclase in the co... more An assay was developed with which to study basic characteristics of an adenylyl cyclase in the corpora allata (CA) of the tobacco hornworm, Manduca sexta. The assay used glands collected and frozen at −80°C, to circumvent the problem of tissue availability. With this protocol for storage of tissue, less than 25% of the enzyme activity in fresh tissue was lost. Substances such as sodium fluoride (NaF) and Gpp(NH)p (a non‐hydrolyzable GTP analog), which typically stimulate the adenylyl cyclases in other insect tissues, increased enzyme activity several‐fold. There was a progressive decrease in the capacity of the CA adenylyl cyclase to be stimulated by NaF during the fifth stadium, suggesting a possible developmental change in the capacity of the associated G protein to be stimulated by NaF. The calcium/calmodulin (CaM) dependence of adenylyl cyclase activity was also investigated. The results demonstrated that addition of up to 10−4 M calcium to assays of enzyme activity in whole gla...
Proceedings in Life Sciences, 1984
The endocrine regulation of insect postembryonic development is generally thought to involve thre... more The endocrine regulation of insect postembryonic development is generally thought to involve three hormones: the prothoracicotropic hormone (PTTH), a cerebral neuropeptide; the steroid hormone 20-hydroxyecdysone; and juvenile hormone, an aliphatic sequiterpene [1]. PTTH is produced by one neurosecretory cell in each hemisphere of the insect brain [2], while 20-hydroxyecdysone is derived from the ecdysone produced by the prothoracic glands (PG) in response to PTTH [3,4]. Juvenile hormone exists in four homologous forms (JH 0, I, II, and III) and is produced by corpora allata (CA) [5]. Although the integration of release of the hormones is critica for their roles in the regulation of insect molting and metamorphosis, the pivot of this regulatory mechanism is the periodic release of PTTH in response to environmental cues. Ecdysone is synthesized and released by the PG in response to PTTH and is then hydroxylated by peripheral tissues to 20-hydroxyecdysone, the hormone that elicits molting. JH acts in conjunction with 20-hydroxyecdysone, presumably at the level of the target tissues to determine the character of the molt [1].
Proceedings of the National Academy of Sciences, 1979
An in vitro assay for the prothoracicotropic hormone has been developed that utilizes an ecdysone... more An in vitro assay for the prothoracicotropic hormone has been developed that utilizes an ecdysone radioimmunoassay to quantify the increase in the rate of ecdysone synthesis elicited by the neurohormonal activation of the prothoracic glands. The rapidity, reproducibility, and accuracy of the assay were maximized by using one member of a gland pair as the control and the other as the test gland. This was possible because the basal rates of ecdysone synthesis by the members of a gland pair were equivalent. Activation was demonstrated to be dose dependent and specific, with prothoracicotropic hormone activity present only in homogenates of brain. The in vitro activation of the prothoracic glands was verified with the Manduca bioassay for the prothoracicotropic hormone in which the morphological responses to the hormone were correlated with increased in vivo ecdysone titers. These results provide unequivocal evidence that the activation of the prothoracic glands by the prothoracicotropi...
The Anatomical Record, 2004
... Coulehan JL, Williams PC, Landis D, Naser C. 1995. The first patient: reflections and stories... more ... Coulehan JL, Williams PC, Landis D, Naser C. 1995. The first patient: reflections and stories about the anatomy cadaver. Teach Learn Med 7: 6166. Dinsmore CE, Daugherty S, Zeitz HJ. 1999. Teaching and learning gross anatomy. Clin Anat 12: 110114. ...
Insect Neurochemistry and Neurophysiology · 1986, 1986
Regulation of juvenile hormone (JH) synthesis by the corpora allata (CA) is a complex process int... more Regulation of juvenile hormone (JH) synthesis by the corpora allata (CA) is a complex process integrating both stimulatory and inhibitory mechanisms to achieve developmentally precise changes in gland activity. These changes in turn contribute to the fluctuations in the JH hemolymph titer which govern post-embryonic development. Recent evidence indicates that stimulation of the CA is effected in some systems by neuropeptides termed allatotropins, and inhibition of the CA by allatostatic factors has also been suggested (Tobe and Stay, 1985). However, comparatively little is known of the nature of these moieties.
Insect Biochemistry, 1987
A positive interendocrine control by 20-hydroxyecdysone regulates the corpora allata (CA) and thu... more A positive interendocrine control by 20-hydroxyecdysone regulates the corpora allata (CA) and thus the hemolymph titers of the juvenile hormones (JHs) during the fourth and fifth larval stadia of the tobacco homworm, Manduca sexta. The effect of 20-hydroxyecdysone is exerted via the brain-corpora cardiaca (Br~C), and the kinetics of stimulation by the hormone suggest that its Control of the CA is indirect, possibly involving neural effectors. Co-incubation of precommitment CA with Br-CC resulted in a stimulation of the synthesis of JH I acid equivalent to that achieved by the incubation of brain-corpora cardiaca-corpora allata (Br-CC-CA) with 20-hydroxyedcysone, suggesting that a diffusible regulatory factor may be involved in the stimulation. During pharate pupal development, a close temporal relationship exists between the drop in the ecclysteroid titer and declines in CA activity and the JH hemolymph titer, suggesting that 20-hydroxyecdysone may now inhibit the CA. Incubations of day 6 Br-CC-CA with physiological concentrations of 20-hydroxyccdysone resulted in an apparent dosedependent inhibition of CA activity. Thus in Manduca, 20-hydroxyecdysone may exert varying stagespecific interendocrine effects on the CA which direct the postembryonic development of this species.
Metamorphosis, 1981
In the swamps and forests of the Devonian era some 350 million years ago, there emerged a group o... more In the swamps and forests of the Devonian era some 350 million years ago, there emerged a group of animals that today can be found in virtually every ecological niche on earth. With the number of their species variously estimated at 1–10 million, the insects display an evolutionary virtuosity unequaled by the rest of the animal kingdom combined. Within 100 million years of the first appearance of these arthropods, the adaptive features that permitted their ecological conquest had evolved, among them small size, functional wings, and a unique specialization of the life cycle known as metamorphosis.
Tissue and Cell, 1977
Three major groups of neurosecretory cells are described in the larval brain of Galleria mellonel... more Three major groups of neurosecretory cells are described in the larval brain of Galleria mellonella at two different times during the last larval instar and in larval brains after 72 hr of culture in vitro. The medial group in vivo consists of four distinct neurosecretory cell types, based on characteristic size and morphology, while the posterior and lateral groups each contain a single distinct type of neurosecretory cell. Morphological differences between the same neurosecretory cells at the different times during the last instar are most apparent in the lateral L-1 cells and in the medial M-2 cells, where pleiomorphism is particularly evident in the size, density and accumulations of neurosecretory granules. The only neurosecretory cells in which apparent synthesis of neurosecretory granules is still observed after culture of the brain in vitro are the medial M-2 cells. The other neurosecretory cell types show no accumulation of neurosecretory granules nor new synthesis of neurosecretory material, but are similar to neurosecretory cells in the brain in vivo in all other respects. The morphology of the neurosecretory cells in the larval brain in vivo and in vitro is discussed in relation to their appearance at the light microscopic level and to a known neurohormonal function of the brain which is maintained during 72 hr in vitro.
The Anatomical Record Part B: The New Anatomist, 2005
This article is based on a presentation of the same name given on 20 April 2004 at a symposium en... more This article is based on a presentation of the same name given on 20 April 2004 at a symposium entitled "Faculty Development: Funding Resources for Education Projects" at the annual meeting of the American Association of Anatomists in Washington, DC. It discusses various lessons learned by the authors from their own work on the development of an educational tool and the assessment of its use with funding from an educational research grant, as well as tips and tools gathered from other education researchers. The material is organized into two sections. The first provides information and suggestions useful in the development of an educational project in anatomy and the preparation of the grant application. The second consists of insights that may help ensure that the funded grant is successful.
Proceedings of the National Academy of Sciences, 1979
The distribution of prothoracicotropic hormone in the pupal brain of Manduca sexta has been deter... more The distribution of prothoracicotropic hormone in the pupal brain of Manduca sexta has been determined by an in vitro assay for prothoracic gland activation. Prothoracicotropic activity was observed in both the brain and retrocerebral complex, but predominantly in the dorosolateral regions of the protocerebrum. Of the two groups of neurosecretory cells present in this area of the brain, only the two lateral type III neurosecretory cells exhibited significant prothoracicotropic hormone activity. Further analysis revealed that the neurohormone was localized in only one of the two type III cells, suggesting that a single neurosecretory cell in each hemisphere is the source of the hormone at the stage examined (day 0). Prothoracicotropic hormone activity was detected in both the corpora allata and the corpora cardiaca, but the corpora allata contained 2 to 9 times the activity of the corpora cardiaca, depending on developmental stage. The significantly higher level of activity in the co...
Molecular and Cellular Endocrinology, 1994
Injection of dibutyryl-cAMP prevents cuticular melanization of black Manduca sexta larvae, whose ... more Injection of dibutyryl-cAMP prevents cuticular melanization of black Manduca sexta larvae, whose pigmentation is related to a defect in the control of the corpus allatum. The cAMP analog has no effect in allatectomized black larvae. Significant stimulation of corpus allatum activity was obtained in vitro with compounds which elicit or mimic elevated intracellular cAMP levels (dibutyryl-, 8bromo-, N 6 benzoyl-, and 8-thiomethyl-cAMP, 3-isobutyl-l-methylxanthine), but not with dibutyryl-cGMP. Relatively inactive glands, such as those on day 4 of last larval stadium or from black mutant larvae, were more sensitive to these compounds than glands actively synthesizing JH/JH acid. JH acid synthesis by corpora allata taken after pupal commitment in the last larval stadium (days 6 and 8) was not stimulated by either dibutyryl-cAMP or 3-isobutyl-l-methylxanthine, but day 8 glands appeared to be inhibited by dibutyryl-cAMP. The results indicate that a cAMP second messenger system is involved in the transduction of signals which stimulate JH/JH acid synthesis by Manduca corpora allata prior to pupal commitment and suggest that it may be involved in the inhibition of JH acid synthesis after commitment. They also imply that the proposed hemolymph factor to which the black mutant corpora allata are differentially sensitive interfaces with the cAMP system.
Molecular and Cellular Endocrinology, 1987
When an in vitro assay system and radioimmunoassays specific for juvenile hormones (JH) I and III... more When an in vitro assay system and radioimmunoassays specific for juvenile hormones (JH) I and III were used to probe the effect of day 4 last instar larval brains on JH synthesis by day 0 last instar larval corpora allata (CA) of the tobacco hornworm, Manduca sexta, a selective inhibition of JH I synthesis by the CA was observed. The nature of this inhibition suggested the presence of an allatostatin specific for the synthesis of JH I. Its occurrence in the day 4 brain was demonstrated by the ability of a crude brain extract to inhibit the CA in a dose-dependent manner. The allatostatic factor (ASF) appears to be a protein, based on its heat lability and pronase sensitivity, and it has apparent molecular weights of 6.8 and 13 kDa. Inhibition of JH I synthesis occurs within 1 min of exposure of the CA to the factor and is reversible by 6 h after this exposure. Thus it appears that a cerebral neuropeptide specifically inhibiting JH I synthesis by the CA is present in Manduca on day 4 of the last larval instar, a time when the hemolymph titer of JH must drop to ensure the occurrence of pupal commitment.
Journal of Insect Physiology, 1986
A titre of the total prothoracicotropic hormone (PTTH) activity in the brain of Marzduca sextu wa... more A titre of the total prothoracicotropic hormone (PTTH) activity in the brain of Marzduca sextu was determined at 24-h intervals during the 4th and Sth-larval instars, and early pupal-adult development using an in vitro assay which monitors stimulation of ecdysone synthesis by prothoracic glands in response to FTTH. The titre increases during development in a stepwise manner at those times when PITH release occurs, suggesting that regulation of the synthesis and/or transport of the neurohormone may be linked to its releiise. By contrast, significant decreases in the F'TTH titre were not observed just after times of its release. The relative amounts of the two molecular forms of PTTH, big and small, in brains were determined at times during development just prior to periods of PTTH release, i.e. day 3 of the last-larval instar and day 1 of the pupal period. In the larval brain big PTTH is the principal hormone present, giving it a ratio to small PTTH of 3.9: 1. In the pupal brain, where total PTTH activity has increased about 5-fold over that of the larval brain, the amount of big PTTH was not significantly greater than in larval brains, whereas the amount of small PTTH has increased by 6-fold. This results in a big to small ratio of 0.95 : 1. These changes in the ratios of the two neuropeptides, which appear to be modulated by the light-dark cycle under which the insect develops, may be involved in the regulation of the postembryonic development of Munduca.
Insect Biochemistry and Molecular Biology, 2000
Roux's Archives of Developmental Biology, 1991
... Hans-Jiirgen Bidmon, Noelle Audrey Granger, and Walter Erich Stumpf Department of Cell Biolog... more ... Hans-Jiirgen Bidmon, Noelle Audrey Granger, and Walter Erich Stumpf Department of Cell Biology and Anatomy, 522 Taylor Hall, University of North Carolina ... since c-fos expression can be induced in the spi-nal cord of mammals by traumatic stimuli within 15 rain (Presley et al. ...
General and Comparative Endocrinology, 1987
A previous study of the role of 20-hydroxyecdysone in the regulation of juvenile hormone (JH) bio... more A previous study of the role of 20-hydroxyecdysone in the regulation of juvenile hormone (JH) biosynthesis during pupal commitment in the last (fifth, V) larval instar of Manduca sexta revealed that the increase in the hemolymph edysteroid titer that elicits commitment also stimulates the corpora allata (CA) to synthesize JHs I and III and/or their acids. This stimulation is exerted indirectly via the brain-corpora cardiaca and results in the postcommitment increase in the JH titer that is important for the molt to a pupa. The possibility that a similar form of interendocrine regulation of JH biosynthesis by 20-hydroxyecdysone is involved in the control of larval molting in Manduca was investigated for the molt from the fourth (IV) to the V larval instar. During the IV instar, the increase in the hemolymph ecdysteroid titer and the capacity of the CA to synthesize JHs I and III in vitro correlated temporally in a manner suggestive of CA regulation by 20-hydroxyecdysone. With an in vitro approach, physiological concentrations of 20-hydroxyecdysone (greater than or equal to 1 microgram ml-1 hemolymph) were shown to have a dose-dependent trophic effect on CA activity, specifically stimulating JH I synthesis. Since neither basally active nor stimulated CA contained significant amounts of JH I, it appears that 20-hydroxyecdysone acts at the level of biosynthesis rather than at the level of release. The specificity of 20-hydroxyecdysone stimulation of JH I synthesis was demonstrated by the inability of the biologically inactive ecdysteroids 22-isoecdysone and 5 alpha-ecdysone to activate the glands.(ABSTRACT TRUNCATED AT 250 WORDS)
Journal of Insect Physiology, 1994
A white mutant of the tobacco hornworm, Manduca sexta, was discovered among wild-type, blue-green... more A white mutant of the tobacco hornworm, Manduca sexta, was discovered among wild-type, blue-green larvae in a laboratory colony routinely supplemented with field-collected insects. The mutant is pinkish-white when reared on artificial diet and maintains this coloration from egg hatch through pupation. Spectral analyses showed that the blue chromophore, biliverdin, which is present in the integument and plasma of wild-type, diet and tobacco-reared larvae, was lacking in the white mutant reared on the same diets. Insecticyanin levels determined by radial immunodiffusion in the integument and plasma of the white mutant were half that of normal blue-green larvae. The topical application of increasing amounts of the juvenoid, 2-(l-methyl-2-(4-phenoxyphenoxy)ethoxy)pyridine, to wildtype, day 1 first stadium larvae of M. sexta was positively correlated with the intensity of white coloration, which first appeared in newly molted second instars and was retained until pupation. White-mutant larvae developed slower and were slightly larger than wild-type larvae. The corpora allata from last stadium, day 0 larvae of the white mutant demonstrated a higher rate of JH/JH acid biosynthesis and the hemolymph had a higher titer of JH than the wild type of the same age. These studies suggested that JH may play a role in the regulation of the white phenotype. No differences were noted in the level of JH esterase activity between the two strains during the last stadium. Biliverdin Carotenoid Color Insecticyanin Juvenile hormone Juvenile hormone biosynthesis Juvenile hormone esterase Manduca sexta Tobacco hornworm
Archives of Insect Biochemistry and Physiology, 1995
An assay was developed with which to study basic characteristics of an adenylyl cyclase in the co... more An assay was developed with which to study basic characteristics of an adenylyl cyclase in the corpora allata (CA) of the tobacco hornworm, Manduca sexta. The assay used glands collected and frozen at −80°C, to circumvent the problem of tissue availability. With this protocol for storage of tissue, less than 25% of the enzyme activity in fresh tissue was lost. Substances such as sodium fluoride (NaF) and Gpp(NH)p (a non‐hydrolyzable GTP analog), which typically stimulate the adenylyl cyclases in other insect tissues, increased enzyme activity several‐fold. There was a progressive decrease in the capacity of the CA adenylyl cyclase to be stimulated by NaF during the fifth stadium, suggesting a possible developmental change in the capacity of the associated G protein to be stimulated by NaF. The calcium/calmodulin (CaM) dependence of adenylyl cyclase activity was also investigated. The results demonstrated that addition of up to 10−4 M calcium to assays of enzyme activity in whole gla...
Proceedings in Life Sciences, 1984
The endocrine regulation of insect postembryonic development is generally thought to involve thre... more The endocrine regulation of insect postembryonic development is generally thought to involve three hormones: the prothoracicotropic hormone (PTTH), a cerebral neuropeptide; the steroid hormone 20-hydroxyecdysone; and juvenile hormone, an aliphatic sequiterpene [1]. PTTH is produced by one neurosecretory cell in each hemisphere of the insect brain [2], while 20-hydroxyecdysone is derived from the ecdysone produced by the prothoracic glands (PG) in response to PTTH [3,4]. Juvenile hormone exists in four homologous forms (JH 0, I, II, and III) and is produced by corpora allata (CA) [5]. Although the integration of release of the hormones is critica for their roles in the regulation of insect molting and metamorphosis, the pivot of this regulatory mechanism is the periodic release of PTTH in response to environmental cues. Ecdysone is synthesized and released by the PG in response to PTTH and is then hydroxylated by peripheral tissues to 20-hydroxyecdysone, the hormone that elicits molting. JH acts in conjunction with 20-hydroxyecdysone, presumably at the level of the target tissues to determine the character of the molt [1].
Proceedings of the National Academy of Sciences, 1979
An in vitro assay for the prothoracicotropic hormone has been developed that utilizes an ecdysone... more An in vitro assay for the prothoracicotropic hormone has been developed that utilizes an ecdysone radioimmunoassay to quantify the increase in the rate of ecdysone synthesis elicited by the neurohormonal activation of the prothoracic glands. The rapidity, reproducibility, and accuracy of the assay were maximized by using one member of a gland pair as the control and the other as the test gland. This was possible because the basal rates of ecdysone synthesis by the members of a gland pair were equivalent. Activation was demonstrated to be dose dependent and specific, with prothoracicotropic hormone activity present only in homogenates of brain. The in vitro activation of the prothoracic glands was verified with the Manduca bioassay for the prothoracicotropic hormone in which the morphological responses to the hormone were correlated with increased in vivo ecdysone titers. These results provide unequivocal evidence that the activation of the prothoracic glands by the prothoracicotropi...
The Anatomical Record, 2004
... Coulehan JL, Williams PC, Landis D, Naser C. 1995. The first patient: reflections and stories... more ... Coulehan JL, Williams PC, Landis D, Naser C. 1995. The first patient: reflections and stories about the anatomy cadaver. Teach Learn Med 7: 6166. Dinsmore CE, Daugherty S, Zeitz HJ. 1999. Teaching and learning gross anatomy. Clin Anat 12: 110114. ...
Insect Neurochemistry and Neurophysiology · 1986, 1986
Regulation of juvenile hormone (JH) synthesis by the corpora allata (CA) is a complex process int... more Regulation of juvenile hormone (JH) synthesis by the corpora allata (CA) is a complex process integrating both stimulatory and inhibitory mechanisms to achieve developmentally precise changes in gland activity. These changes in turn contribute to the fluctuations in the JH hemolymph titer which govern post-embryonic development. Recent evidence indicates that stimulation of the CA is effected in some systems by neuropeptides termed allatotropins, and inhibition of the CA by allatostatic factors has also been suggested (Tobe and Stay, 1985). However, comparatively little is known of the nature of these moieties.
Insect Biochemistry, 1987
A positive interendocrine control by 20-hydroxyecdysone regulates the corpora allata (CA) and thu... more A positive interendocrine control by 20-hydroxyecdysone regulates the corpora allata (CA) and thus the hemolymph titers of the juvenile hormones (JHs) during the fourth and fifth larval stadia of the tobacco homworm, Manduca sexta. The effect of 20-hydroxyecdysone is exerted via the brain-corpora cardiaca (Br~C), and the kinetics of stimulation by the hormone suggest that its Control of the CA is indirect, possibly involving neural effectors. Co-incubation of precommitment CA with Br-CC resulted in a stimulation of the synthesis of JH I acid equivalent to that achieved by the incubation of brain-corpora cardiaca-corpora allata (Br-CC-CA) with 20-hydroxyedcysone, suggesting that a diffusible regulatory factor may be involved in the stimulation. During pharate pupal development, a close temporal relationship exists between the drop in the ecclysteroid titer and declines in CA activity and the JH hemolymph titer, suggesting that 20-hydroxyecdysone may now inhibit the CA. Incubations of day 6 Br-CC-CA with physiological concentrations of 20-hydroxyccdysone resulted in an apparent dosedependent inhibition of CA activity. Thus in Manduca, 20-hydroxyecdysone may exert varying stagespecific interendocrine effects on the CA which direct the postembryonic development of this species.
Metamorphosis, 1981
In the swamps and forests of the Devonian era some 350 million years ago, there emerged a group o... more In the swamps and forests of the Devonian era some 350 million years ago, there emerged a group of animals that today can be found in virtually every ecological niche on earth. With the number of their species variously estimated at 1–10 million, the insects display an evolutionary virtuosity unequaled by the rest of the animal kingdom combined. Within 100 million years of the first appearance of these arthropods, the adaptive features that permitted their ecological conquest had evolved, among them small size, functional wings, and a unique specialization of the life cycle known as metamorphosis.
Tissue and Cell, 1977
Three major groups of neurosecretory cells are described in the larval brain of Galleria mellonel... more Three major groups of neurosecretory cells are described in the larval brain of Galleria mellonella at two different times during the last larval instar and in larval brains after 72 hr of culture in vitro. The medial group in vivo consists of four distinct neurosecretory cell types, based on characteristic size and morphology, while the posterior and lateral groups each contain a single distinct type of neurosecretory cell. Morphological differences between the same neurosecretory cells at the different times during the last instar are most apparent in the lateral L-1 cells and in the medial M-2 cells, where pleiomorphism is particularly evident in the size, density and accumulations of neurosecretory granules. The only neurosecretory cells in which apparent synthesis of neurosecretory granules is still observed after culture of the brain in vitro are the medial M-2 cells. The other neurosecretory cell types show no accumulation of neurosecretory granules nor new synthesis of neurosecretory material, but are similar to neurosecretory cells in the brain in vivo in all other respects. The morphology of the neurosecretory cells in the larval brain in vivo and in vitro is discussed in relation to their appearance at the light microscopic level and to a known neurohormonal function of the brain which is maintained during 72 hr in vitro.
The Anatomical Record Part B: The New Anatomist, 2005
This article is based on a presentation of the same name given on 20 April 2004 at a symposium en... more This article is based on a presentation of the same name given on 20 April 2004 at a symposium entitled "Faculty Development: Funding Resources for Education Projects" at the annual meeting of the American Association of Anatomists in Washington, DC. It discusses various lessons learned by the authors from their own work on the development of an educational tool and the assessment of its use with funding from an educational research grant, as well as tips and tools gathered from other education researchers. The material is organized into two sections. The first provides information and suggestions useful in the development of an educational project in anatomy and the preparation of the grant application. The second consists of insights that may help ensure that the funded grant is successful.
Proceedings of the National Academy of Sciences, 1979
The distribution of prothoracicotropic hormone in the pupal brain of Manduca sexta has been deter... more The distribution of prothoracicotropic hormone in the pupal brain of Manduca sexta has been determined by an in vitro assay for prothoracic gland activation. Prothoracicotropic activity was observed in both the brain and retrocerebral complex, but predominantly in the dorosolateral regions of the protocerebrum. Of the two groups of neurosecretory cells present in this area of the brain, only the two lateral type III neurosecretory cells exhibited significant prothoracicotropic hormone activity. Further analysis revealed that the neurohormone was localized in only one of the two type III cells, suggesting that a single neurosecretory cell in each hemisphere is the source of the hormone at the stage examined (day 0). Prothoracicotropic hormone activity was detected in both the corpora allata and the corpora cardiaca, but the corpora allata contained 2 to 9 times the activity of the corpora cardiaca, depending on developmental stage. The significantly higher level of activity in the co...
Molecular and Cellular Endocrinology, 1994
Injection of dibutyryl-cAMP prevents cuticular melanization of black Manduca sexta larvae, whose ... more Injection of dibutyryl-cAMP prevents cuticular melanization of black Manduca sexta larvae, whose pigmentation is related to a defect in the control of the corpus allatum. The cAMP analog has no effect in allatectomized black larvae. Significant stimulation of corpus allatum activity was obtained in vitro with compounds which elicit or mimic elevated intracellular cAMP levels (dibutyryl-, 8bromo-, N 6 benzoyl-, and 8-thiomethyl-cAMP, 3-isobutyl-l-methylxanthine), but not with dibutyryl-cGMP. Relatively inactive glands, such as those on day 4 of last larval stadium or from black mutant larvae, were more sensitive to these compounds than glands actively synthesizing JH/JH acid. JH acid synthesis by corpora allata taken after pupal commitment in the last larval stadium (days 6 and 8) was not stimulated by either dibutyryl-cAMP or 3-isobutyl-l-methylxanthine, but day 8 glands appeared to be inhibited by dibutyryl-cAMP. The results indicate that a cAMP second messenger system is involved in the transduction of signals which stimulate JH/JH acid synthesis by Manduca corpora allata prior to pupal commitment and suggest that it may be involved in the inhibition of JH acid synthesis after commitment. They also imply that the proposed hemolymph factor to which the black mutant corpora allata are differentially sensitive interfaces with the cAMP system.
Molecular and Cellular Endocrinology, 1987
When an in vitro assay system and radioimmunoassays specific for juvenile hormones (JH) I and III... more When an in vitro assay system and radioimmunoassays specific for juvenile hormones (JH) I and III were used to probe the effect of day 4 last instar larval brains on JH synthesis by day 0 last instar larval corpora allata (CA) of the tobacco hornworm, Manduca sexta, a selective inhibition of JH I synthesis by the CA was observed. The nature of this inhibition suggested the presence of an allatostatin specific for the synthesis of JH I. Its occurrence in the day 4 brain was demonstrated by the ability of a crude brain extract to inhibit the CA in a dose-dependent manner. The allatostatic factor (ASF) appears to be a protein, based on its heat lability and pronase sensitivity, and it has apparent molecular weights of 6.8 and 13 kDa. Inhibition of JH I synthesis occurs within 1 min of exposure of the CA to the factor and is reversible by 6 h after this exposure. Thus it appears that a cerebral neuropeptide specifically inhibiting JH I synthesis by the CA is present in Manduca on day 4 of the last larval instar, a time when the hemolymph titer of JH must drop to ensure the occurrence of pupal commitment.
Journal of Insect Physiology, 1986
A titre of the total prothoracicotropic hormone (PTTH) activity in the brain of Marzduca sextu wa... more A titre of the total prothoracicotropic hormone (PTTH) activity in the brain of Marzduca sextu was determined at 24-h intervals during the 4th and Sth-larval instars, and early pupal-adult development using an in vitro assay which monitors stimulation of ecdysone synthesis by prothoracic glands in response to FTTH. The titre increases during development in a stepwise manner at those times when PITH release occurs, suggesting that regulation of the synthesis and/or transport of the neurohormone may be linked to its releiise. By contrast, significant decreases in the F'TTH titre were not observed just after times of its release. The relative amounts of the two molecular forms of PTTH, big and small, in brains were determined at times during development just prior to periods of PTTH release, i.e. day 3 of the last-larval instar and day 1 of the pupal period. In the larval brain big PTTH is the principal hormone present, giving it a ratio to small PTTH of 3.9: 1. In the pupal brain, where total PTTH activity has increased about 5-fold over that of the larval brain, the amount of big PTTH was not significantly greater than in larval brains, whereas the amount of small PTTH has increased by 6-fold. This results in a big to small ratio of 0.95 : 1. These changes in the ratios of the two neuropeptides, which appear to be modulated by the light-dark cycle under which the insect develops, may be involved in the regulation of the postembryonic development of Munduca.
Insect Biochemistry and Molecular Biology, 2000
Roux's Archives of Developmental Biology, 1991
... Hans-Jiirgen Bidmon, Noelle Audrey Granger, and Walter Erich Stumpf Department of Cell Biolog... more ... Hans-Jiirgen Bidmon, Noelle Audrey Granger, and Walter Erich Stumpf Department of Cell Biology and Anatomy, 522 Taylor Hall, University of North Carolina ... since c-fos expression can be induced in the spi-nal cord of mammals by traumatic stimuli within 15 rain (Presley et al. ...