Endocrine activity during caste differentiation in Zootermopsis angusticollis Hagen (Isoptera): a morphometric and autoradiographic study

1975 ◽  
Vol 53 (11) ◽  
pp. 1690-1700 ◽  
Author(s):  
Chih-Ming Yin ◽  
Cedric Gillott
Keyword(s):  
Autoradiographic Study ◽  
Neurosecretory Cells ◽  
Caste Differentiation ◽  
Corpora Allata ◽  
Synthetic Activity ◽  
Cell Diameter ◽  
Endocrine Control ◽  
Endocrine Activity ◽  
Zootermopsis Angusticollis ◽  
Primary Reproductives

The diameters of the median neurosecretory cells (MNC) and their nuclei, and the volumes of the corpora cardiaca (CC) and corpora allata (CA) were measured in termites (Zootermopsis angusticollis) of differing age, sex, and caste. The synthetic activities of the MNC and CA were estimated autoradiographically.No significant differences in the diameters of the MNC and their nuclei were observed between insects of differing age, sex, and caste, with the exception of primary reproductives whose MNC are significantly larger than those of larvae of the same instar. The six types of MNC distinguishable histologically differ in their nuclear diameter : cell diameter ratios and in their rates of [3H]uridine and [3H]cystine incorporation.The volumes and (or) synthetic activities of the CA change markedly during the differentiation of reproductives and soldiers. The CA of recently molted primary and supplementary reproductives are several times larger than those of larvae and nymphs of the previous instar, yet their synthetic activity remains low. In contrast, the CA of presoldiers and soldiers are only slightly larger than those of previous instar larvae, but show high synthetic activity. The data are discussed in terms of the endocrine control of caste differentiation.

Morphology and histology of the endocrine glands of Zootermopsis angusticollis Hagen (Isoptera)

1972 ◽  
Vol 50 (12) ◽  
pp. 1537-1547 ◽  
Author(s):  
Cedric Gillott ◽  
Chih-Ming Yin
Keyword(s):  
Cell Types ◽  
Cell Number ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Endocrine Glands ◽  
Histological Changes ◽  
Secretory Cycle ◽  
Zootermopsis Angusticollis ◽  
Primary Reproductives ◽  
Median Neurosecretory Cells

The morphology and histology of the endocrine glands of the various castes of Zootermopsis angmticollis were examined. Six types of median neurosecretory cells are distinguishable by size and stain affinity. No differences in the relative numbers of these cell types among castes can be seen. It is postulated that they may be different forms of the same cell during its synthetic and secretory cycle. Lateral neurosecretory cells can be identified consistently only in mature primary reproductives of both sexes. In the corpora cardiaca two types of cells occur; the fuchsinophilic cells are distributed generally whereas the cells that take up counterstain are restricted to the center of the gland. Intercellular neurosecretory cell product is found throughout the gland. No histological changes associated with the formation of particular castes were observed. The corpora allata (CA) vary in size and histological appearance according to caste but not sex. The CA of reproductives (primary and supplementary) and presoldiers are larger than those of juveniles of the same instar; those of soldiers are about the same size as those of the corresponding juvenile stage. These size increases are due mainly to changes in the ratio cytoplasmic diameter: nuclear diameter of the constituent cells and not to an increase in cell number. The H-shaped molt glands, which, as in other pterygote insects, disappear within a few days of the imaginal molt, are composed of a large prothoracic portion and a smaller cephalic ('ventral gland') portion extending anteriorly and dorsally. Histologically the two components are indistinguishable. Running through the glands are thin strands of muscle.

Endocrine control of caste differentiation in Zootermopsis angusticollis Hagen (Isoptera)

1975 ◽  
Vol 53 (11) ◽  
pp. 1701-1708 ◽  
Author(s):  
Chih-Ming Yin ◽  
Cedric Gillott
Keyword(s):  
Juvenile Hormone ◽  
Methyl Ether ◽  
Caste Differentiation ◽  
Corpus Allatum ◽  
Endocrine Control ◽  
Reproductive Differentiation ◽  
Zootermopsis Angusticollis ◽  
Supplementary Reproductives

The effect of injection of Röller's juvenile hormone (JH) or farnesyl methyl ether (FME) on differentiation of supplementary reproductives and presoldiers of Zootermopsis angusticollis has been studied. Early in the stadium (that is, during the competence period) Röller's JH and FME inhibit differentiation. When injected after the competence period the substances do not alter the rate of supplementary reproductive differentiation in orphaned colonies but enhance presoldier differentiation in soldierless colonies provided that there is a sufficient number of supplementary reproductives present.A modified version of Lüscher's (1960) hypothesis for the endocrine control of caste differentiation is proposed. It is suggested that all the developmental possibilities that exist in the termite colony can be explained on the basis of a single corpus allatum hormone produced in different quantities and at different times within the stadium.

STUDIES IN THE MODE OF ACTION OF ROYAL JELLY IN HONEYBEE DEVELOPMENT: IV. DEVELOPMENT WITHIN THE BRAIN AND RETROCEREBRAL COMPLEX OF FEMALE HONEYBEE LARVAE

1964 ◽  
Vol 42 (2) ◽  
pp. 229-233 ◽  
Author(s):  
Sylvia J. Canetti ◽  
R. W. Shuel ◽  
S. E. Dixon
Keyword(s):  
Larval Instar ◽  
Quantitative Difference ◽  
Progressive Increase ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Endocrine Activity ◽  
Nuclear Degeneration ◽  
Histological Criteria ◽  
Caste Differences ◽  
The Brain

Histological evidence is presented for a caste difference in endocrine activity during the critical period of determination in the larval honeybee. Until the last larval instar, neurosecretory cells in the brain of the honeybee larva remain undifferentiated. During this undifferentiated period there is a quantitative difference in apparent activity, as evidenced by the frequency of occurrence of cytoplasmic particles in certain large neuroblasts. Whereas the histological criteria for neurosecretory cells cannot be fulfilled, the brain is presumably exercising a regulatory role in growth and development. These large neuroblasts with phloxinophil inclusions are the likely candidate cells. Between the ages of 40 and 80 hours there is considerably more activity in the queen larva than in the worker. At this time the corpora cardiaca are non-existent as discrete organs.Changes in size and histological appearance of the corpora allata indicate a progressive increase in activity during the first 3 days. In the queen, nuclear degeneration with an apparent cessation of activity occurs in the third and fourth instars. In the late larval and propupal stages a reorganisation occurs. This reorganization is characterized by the reappearance of a discrete nuclear membrane and well-defined nuclei. The presence of intercellular spaces, however, suggests a lack of activity. The corpora allata of worker larvae attain a smaller size during larval life; nuclear degeneration and subsequent reorganization have not been observed in worker larvae.The significance of these caste differences in endocrine activity is discussed.

AN AUTORADIOGRAPHIC STUDY OF ENDOCRINE ACTIVITY FOLLOWING FRONTAL GANGLIONECTOMY IN VIRGIN FEMALES OF MELANOPLUS SANGUINIPES (ORTHOPTERA: ACRIDIDAE)

1970 ◽  
Vol 102 (9) ◽  
pp. 1083-1088 ◽  
Author(s):  
C. Gillott ◽  
G. S. Dogra ◽  
Al B. Ewen
Keyword(s):  
Type A ◽  
Autoradiographic Study ◽  
Neurosecretory Cells ◽  
Corpus Allatum ◽  
Melanoplus Sanguinipes ◽  
Endocrine Activity ◽  
Frontal Ganglion

AbstractThe synthetic ability of type-A neurosecretory cells (NSC) and corpus allatum (CA) was investigated autoradiographically in both normal virgin females and those from which the frontal ganglion had been removed. Incorporation of 3H-cystine and 3H-uridine into the NSC was significantly lower in frontal ganglionectomized insects than in controls. There appeared to be no relationship between the level of isotope uptake and the amount of stainable material in the NSC. Ability of the CA to incorporate 3H-uridine seemed unaffected by the operation.

An Autoradiographic Study of Neurosecretory Cell Activity of Allatectomized Females of the Grasshopper, Melanoplus sanguinipes (Fab.)

1975 ◽  
Vol 30 (7-8) ◽  
pp. 511-515
Author(s):  
G. S. Dogra
Keyword(s):  
Neurosecretory Cell ◽  
Cell Activity ◽  
Secretory Activity ◽  
Autoradiographic Study ◽  
Neurosecretory Cells ◽  
Corpus Allatum ◽  
High Uptake ◽  
Melanoplus Sanguinipes ◽  
Gradual Accumulation ◽  
Activity Cycles

Abstract Neurosecretory cell activity was studied autoradiographically in the allatectomized females of Melanoplus sanguinipes on every alternate day and in the normal control females on every fourth day for a period of 34 days. Experimental females exhibited five activity cycles against the two recorded by the control females. There was a comparatively high uptake of [3H] cystine by the neurosecretory cells of the experimental females on a particular day. During the first 12 days there was no accumulation of stainable colloid in their system. By the 24th day there was a slow and gradual accumulation of the colloids in the cells and their tracts so that on 34th day the system was well loaded with these colloids. In control females there was good accumulation of the stainable material during the first 12 days and then it declined so that 20 day old females had very little material in their system. This was followed by a massive accumulation of the stained colloids by 32nd day. The uptake of [3H] uridine was very high in the nerve-regenerate of the experimental females, and there were six cycles of secretory activity during the period of experimentation. The corpus allatum of control females, like their neurosecretory cells, exhibited only two activity cycles. Since the activity of the neurosecretory cells parallels the RNA synthesis in the nerve-regenerate, it is postulated that the neurosecretory cells produce factors for nerve-regeneration. On the basis of high uptake of isotopes by the neurosecretory cells of those allatectomized females in which the oocytes were mature it is suggested that the hormone (s) produced by the neurosecretory cells are perhaps responsible for oocyte maturation in these allatectomized females.

Changes in cell number and activity of the corpora allata of the cockroach Diploptera punctata: a role for mating and the ovary

1984 ◽  
Vol 62 (11) ◽  
pp. 2178-2182 ◽  
Author(s):  
S. S. Tobe ◽  
N. Clarke ◽  
B. Stay ◽  
R. P. Ruegg
Keyword(s):  
Juvenile Hormone ◽  
Cell Number ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Surgical Removal ◽  
Gonotrophic Cycle ◽  
Biosynthetic Activity ◽  
Diploptera Punctata ◽  
Number Of Cells ◽  
Mated Female

The corpora allata (CA) of mated female Diploptera punctata showed an increase in cell number from 6000 cells/CA on the day of emergence to a maximum of about 9000 cells/CA by day 5. The number of cells per CA then declined and, by day 8, the CA was composed of about 6000 cells. In the normal mated animal, the previously established increase in biosynthetic activity of the CA correlated with the increase in number of cells in the CA. In virgin females no significant change in cell number was observed during this period and this correlates with the demonstrated low and constant rates of juvenile hormone (JH) biosynthesis. Following ovariectomy, however, an increase in cell number occurred (to 10 000 cells/CA) by day 5 and cell number remained elevated until at least day 8. Low rates of JH biosynthesis have been observed previously in ovariectomized females and thus the increase in cell number observed in these females is not accompanied by a corresponding increase in biosynthetic activity. The cell number of the CA in ovariectomized females was reduced by injection of 20-hydroxyecdysone. We propose that either mating or surgical removal of inhibitory signals from cerebral neurosecretory cells permits the proliferation of the cells of the CA. We also propose that factors from the ovary are responsible for both the initiation of the cycle of JH biosynthesis and the reduction of CA cell number at the end of the gonotrophic cycle.

The Stomodaeal Nervous System, Neurosecretion, and Related Endocrine and Nervous Structures in Aedes aegypti (L.) (Diptera: Culicidae)

1964 ◽  
Vol 96 (1-2) ◽  
pp. 105-106 ◽  
Author(s):  
L. Burgess ◽  
J. G. Rempel
Keyword(s):  
Nervous System ◽  
Aedes Aegypti ◽  
Common Property ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Prothoracic Gland ◽  
Neurosecretory Material ◽  
Purple Colour ◽  
Aldehyde Fuchsin ◽  
The Common

This exhibit represents some portions of a study of the stomodaeal nervous system, neurosecretory cells, corpora allata, corpora cardiaca, and prothoracic gland cells in post-embryonic stages of Aedes aegypti (L.), the yellow fever mosquito. Some of these structures share the common property of being involved in the production of hormones.Mosquitoes were reared under standard conditions. Larvae, pupae and adults were fixed at timed intervals in histological fixatives. Sectioned specimens were stained in Gomori's aldehyde-fuchsin, Gomori's chrome-haematoxyh-phloxin and other stains. The aldehyde-fuchsin technique, which imparted a bright purple colour to neurosecretory material, was particularly useful. Vita1 staining with methylene blue was used to trace the stomodaeal nervous system

THE STOMODAEAL NERVOUS SYSTEM, THE NEUROSECRETORY SYSTEM, AND THE GLAND COMPLEX IN AEDES AEGYPTI (L.) (DIPTERA: CULICIDAE)

1966 ◽  
Vol 44 (4) ◽  
pp. 731-765 ◽  
Author(s):  
L. Burgess ◽  
J. G. Rempel
Keyword(s):  
Nervous System ◽  
Aedes Aegypti ◽  
Neurosecretory Cells ◽  
Sensory Nerves ◽  
Corpora Allata ◽  
Prothoracic Gland ◽  
Neurosecretory System ◽  
Endocrine Gland ◽  
Adult Females ◽  
The Central Nervous System

The stomodaeal nervous system in Aedes aegypti (L.) possesses a frontal, a hypocerebral, and two ventricular ganglia. It innervates parts of the alimentary tract and some muscles of ingestion, and it has associated with it certain motor nerves from the central nervous system, and sensory nerves. In larvae these sensory nerves originate from tactile head hairs, and from sensilla on the epipharyngeal apparatus. The neurosecretory system is generally similar to that in other insects. The pars intercerebralis contains three paired groups of neurosecretory cells, with axons from one pair leading to the dorsal mass, a structure fused to the hypocerebral ganglion. Evidence suggests that the dorsal mass functionally corresponds to part of the corpus cardiacum of other insects. However, what seem to be cardiacum cells are located some distance away in two groups in the endocrine gland complex in the thorax. The corpora allata, also contained in this complex, can first be recognized as distinct organs early in the third instar. In the corpora allata of adult females, cell division and an increase in the amount of cytoplasm occur soon after emergence, rather than after a blood meal. When adult females are about 1 day old, vacuoles begin to develop in the corpora allata. Cells in the gland complex corresponding to the prothoracic gland cells begin to histolyze in the pupa, and most of them are completely broken down before adults are 1 day old.

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