A neuroendocrine relationship between the nematode Hammerschmidtiella diesingi and its insect host, Blatta orientalis

Parasitology ◽  
1970 ◽  
Vol 61 (1) ◽  
pp. 101-110 ◽  
Author(s):  
R. Gordon
Keyword(s):  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Insect Host ◽  
Histological Studies ◽  
Corpora Cardiaca ◽  
Blatta Orientalis ◽  
Adult Nematode ◽  
Median Neurosecretory Cells ◽  
Reproductive Processes ◽  
Terminal Oocyte

Various endocrine operations were performed on the adult female cockroach Blatta orientalis and the adult populations of the nematode Hammerschmidtiella diesingi were recorded 2 or 4 weeks later. Cautery of the median neurosecretory cells (m.n.c.) caused a significant reduction in total numbers of adult nematodes after 2 or 4 weeks; after 2 weeks, removal of the retrocerebral complex (corpora cardiaca plus corpora allata) caused a significant overall reduction in the adult nematode burden and this could not be prevented by reimplanting the corpora allata immediately after the retrocerebral complex had been removed.Anomalies appeared in the data when the sex of the parasite was examined and this may be related to a possible postembryonic mode of sex determination.Both m.n.c. cautery and removal of the retrocerebral complex suppressed host terminal oocyte development and ootheca production, whilst reimplantation of corpora allata into ‘retrocerebralectomized’ cockroaches allowed reproductive processes to continue normally. Hence, the m.n.c. and corpora allata are essential for host egg development.Histological studies showed a profound reduction in fuchsinophilic material in the corpora cardiaca of m.n.c. cauterized cockroaches.Although the m.n.c. may affect the nematode directly or indirectly, a direct effect on the parasite by the corpora allata is unlikely.

Activity of the Corpora Allata during Pupal Diapause in Mimas tiliae (Lepidoptera)

1958 ◽  
Vol s3-99 (46) ◽  
pp. 171-180
Author(s):  
K.C. HIGHNAM
Keyword(s):  
Low Temperature ◽  
Oxygen Uptake ◽  
Fat Body ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Histological Observation ◽  
Corpora Cardiaca ◽  
Pupal Diapause ◽  
The Brain

Histological observation indicates that the corpora allata of Mimas tiliae are secretory during pupal diapause, but become inactive by the end of the low-temperature period which terminates diapause. Removal of the corpora allata, together with the corpora cardiaca, from the diapausing pupa increases the thickness of the hypodermis and decreases the number of fat-body inclusions (compared with operated controls), but does not result in any visible signs of diapause break. The oxygen uptake of the pupa increases by about 60% by the end of the low-temperature period, compared with the diapausing pupa. It is probable that the corpora allata play some part in the maintenance of diapause, possibly by exercising some control over the fat-body metabolism. This role is subservient to that of the neurosecretory cells in the brain, together with their associated corpora cardiaca.

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.

Changes in the protein concentration and volume of the haemolymph in relation to yolk deposition, ovariectomy, allatectomy, and cautery of the median neurosecretory cells in Melanoplus sanguinipes

1977 ◽  
Vol 55 (1) ◽  
pp. 97-103 ◽  
Author(s):  
R. H. Elliott ◽  
C. Gillott
Keyword(s):  
Protein Synthesis ◽  
Total Protein ◽  
Protein Concentration ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Total Protein Content ◽  
Concentration Increase ◽  
Protein Levels ◽  
Low Protein ◽  
Median Neurosecretory Cells

The protein concentration and volume of the haemolymph may change with no apparent relation to one another in normal, ovariectomized, allatectomized, and median-neurosecretorycell-cauterized (mNSC-cauterized) females. Therefore, protein levels in the haemolymph are more meaningfully expressed in terms of the total protein content. In normal females, fluctuations in the haemolymph volume tend to parallel changes in the protein concentration during the first and subsequent gonotrophic periods. However, significantly less protein accumulates during the latter periods. The suggestion that these fluctuations partly reflect changes in the vitellogenic requirements of the oocytes is supported by the finding that both the volume and protein concentration increase significantly after ovariectomy.Allatectomy or mNSC cautery prevents the normal accumulation of protein in the haemolymph. In allatectomized females, the slight increase in protein concentration is accompanied by a decline in haemolymph volume. Cautery of the mNSC, provided it is performed within 3 h of emergence, results in a low protein concentration but has no effect on the haemolymph volume. The observations are discussed in terms of the corpora allata and mNSC control of haemolymph protein synthesis.

Histological changes in the ovary in relation to yolk deposition, allatectomy, and destruction of the median neurosecretory cells in Melanoplus sanguinipes

1976 ◽  
Vol 54 (2) ◽  
pp. 185-192 ◽  
Author(s):  
R. H. Elliott ◽  
C. Gillott
Keyword(s):  
Brush Border ◽  
Follicle Cell ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Uptake Mechanism ◽  
Histological Changes ◽  
Pinocytotic Vesicles ◽  
Median Neurosecretory Cells

Histological changes in the ovary during periods of yolk deposition suggest that differentiation of the follicular epithelium and oolemma is an essential prerequisite to the pinocytotic uptake of protein into the oocytes. Before vitellogenesis, intercellular spaces form between adjacent follicle cells, and a brush border appears along the oocyte surface. The presence of protein within these spaces and of elementary yolk spheres along the brush border suggests that protein reaches the oocyte by an intercellular route.Accumulation of yolk does not occur after allatectomy or median neurosecretory cell (mNSC) cautery. Allatectomy inhibits the differentiation of the follicle cells and oolemma. In contrast, after mNSC cautery, differentiation occurs but the pinocytotic vesicles pinched off from the oolemma are empty, indicating that the availability of yolk precursors, not the uptake mechanism, has been affected. In addition, the appearance of secretion in the lateral oviducts is prevented by allatectomy, but merely delayed by mNSC cautery. The findings indicate that the corpora allata, but not the mNSC, are the source of a gonadotropin that regulates follicle-cell differentiation and the development of secretion in the lateral oviducts.

Reproductive growth in normal, allatectomized, median-neurosecretory-cell-cauterized, and ovariectomized females of Melanoplus sanguinipes

1976 ◽  
Vol 54 (2) ◽  
pp. 162-171 ◽  
Author(s):  
C. Gillott ◽  
R. H. Elliott
Keyword(s):  
Body Weight ◽  
Fat Body ◽  
Neurosecretory Cell ◽  
Initial Period ◽  
Somatic Growth ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Oocyte Growth ◽  
Median Neurosecretory Cells ◽  
Growth Changes

Changes in the weight of the whole insect, fat body, and ovary during successive gonotrophic cycles have been measured. The effects of ovariectomy, cautery of the median neurosecretory cells (mNSC), or removal of the corpora allata (CA) on the development of the fat body and reproductive system have also been observed.After an initial period of somatic growth, changes in body weight are very largely due to growth of the proximal oocytes and to oviposition. Yolk deposition begins when the oocytes are1.0 mm long and occurs most rapidly during the final stages of their development. Vitellogenesis begins in the penultimate oocytes when the proximal oocytes are 3.0–3.5 mm long. Ovariectomy results in a significant increase in the weight of the fat body. Removal of the CA prevents oocyte development beyond the 1-mm stage and production of secretion in the lateral oviducts. Both effects can be reversed by treating operated insects with juvenile hormone. Cautery of the mNSC, provided it is carried out within 3 h of emergence, also inhibits oocyte growth and delays the appearance of secretion in the lateral oviducts.

Morphology and histology of the cephalic endocrine glands of the damselfly, Coenagrion angulatum Walker (Zygoptera: Odonata)

1969 ◽  
Vol 47 (6) ◽  
pp. 1187-1192
Author(s):  
C. Gillott
Keyword(s):  
Sexual Maturation ◽  
Adult Life ◽  
Secretory Activity ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Single Pair ◽  
General Shape ◽  
Corpora Cardiaca ◽  
Ventral Glands ◽  
The Brain

In Coenagrion angulatum Walk. there is a single group of neurosecretory cells, median in position, on each side of the brain. The A- and B-type cells are intermingled within each group and their axons form a single pair of nerves to the corpora cardiaca. No pattern of secretory activity is discernible in the B cells. The A cells of mature nymphs and newly emerged adults are loaded with fuchsinophilic droplets but the amount of stainable material decreases as sexual maturation proceeds. A corresponding change in the location and amount of fuchsinophilic material takes place in the corpora cardiaca. In the mature nymph and young adult there is much material distributed throughout the gland. During sexual maturation it becomes less in quantity and restricted to a position adjacent to the aorta wall. A pair of stout, strongly fuchsinophilic nerves leaves the anterior end of the corpora cardiaca and passes ventrolaterally. These bypass the corpora allata and enter the thorax. Their point of termination has not been determined in this study. The corpora allata are small, roundish-oval bodies in the mature juvenile and newly emerged adult damselfly. While retaining their general shape they increase in volume several fold as sexual maturation takes place. The ventral glands are large, lobular structures in mature nymphs. Immediately after emergence they shrink and their cells become pycnotic. Generally by the fourth day of adult life they have disappeared. The results of this study are discussed in relation to those of other authors for the Odonata.

Levels of tryptophan, 5-hydroxytryptamine, and dopamine in some tissues of the cockroach Periplaneta americana

1986 ◽  
Vol 64 (12) ◽  
pp. 2669-2673 ◽  
Author(s):  
B. Duff Sloley ◽  
Roger G. H. Downer ◽  
Cedric Gillott
Keyword(s):  
Nervous Tissue ◽  
High Performance ◽  
Periplaneta Americana ◽  
Corpora Allata ◽  
Suboesophageal Ganglion ◽  
Corpora Cardiaca ◽  
Thoracic Ganglia ◽  
Frontal Ganglion ◽  
Low Levels ◽  
Immunohistochemical Studies

Tryptophan, 5-hydroxytryptamine, and dopamine were measured in the frontal ganglion, corpora cardiaca, corpora allata, nerves of the suboesophageal ganglion, nerves of the thoracic ganglia, gut, testes, and ovaries of the cockroach Periplaneta americana using high performance liquid chromatography with electrochemical detection. 5-Hydroxytryptamine was demonstrated in the frontal ganglion, corpora cardiaca, corpora allata, and nerves of the suboesophageal ganglion but not in the gut, testes, ovaries, or nerves of the thoracic ganglia. These results quantitatively confirm immunohistochemical studies of 5-hydroxytryptamine in neurohaemal and nonneuronal tissues of the cockroach. Dopamine was found in all neurohaemal and nervous tissue examined. Dopamine was also found at low levels in the rectum. Tryptophan was found in all tissues examined.

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.

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