The influence of the brain hormone on retention of blood in the mid-gut of the mosquito Aedes aegypti (L.) III. The involvement of the ovaries and ecdysone

1979 ◽  
Vol 205 (1160) ◽  
pp. 411-421 ◽  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Ovarian Development ◽  
Neurosecretory Cells ◽  
Direct Result ◽  
Corpus Cardiacum ◽  
Egg Development ◽  
The Brain

Most female mosquitoes require a blood-meal in order to produce mature oöcytes. An egg development neurosecretory hormone (EDNH), which is produced in the medial neurosecretory cells (m. n. c.) of the brain and stored in the corpus cardiacum, is released into the haemolymph following the ingestion of blood and is essential for the promotion of ovarian development to maturity. It has been shown that a factor from the m. n. c., presumably EDNH, is necessary if the blood-meal is to be retained in the mid-gut until the oöcytes approach maturity. The present paper shows that retention is not a direct result of the action of EDNH, but is dependent on the ovaries and may well involve ecdysone. Removal of the ovaries before a blood-meal leads to early haem-defaecation, but delay can be restored by injection of ecdysterone. Sub-threshold feeders and mosquitoes decapitated immediately after the intake of blood, each of which would be expected to eliminate the blood-meal early, also show a delay in the onset of haem-defaecation when injected with ecdysterone. Further, both in ovariectomized insects and sub-threshold feeders the time of onset of haem-defaecation is associated with the dose of ecdysterone given.

The influence of the brain hormone on retention of blood in the mid-gut of the mosquito Aedes aegypti (L.) - II. Early elimination following removal of the medial neurosecretory cells of the brain

1978 ◽  
Vol 202 (1147) ◽  
pp. 307-311 ◽  
Keyword(s):  
Aedes Aegypti ◽  
Oocyte Maturation ◽  
Blood Meal ◽  
Neurosecretory Cells ◽  
Secretory Cells ◽  
Corpus Cardiacum ◽  
Egg Development ◽  
Pars Intercerebralis ◽  
The Brain

Development of the oöcytes beyond the resting stage to maturity in mosquitoes is triggered by an egg development neurosecretory hormone from the brain. This hormone is produced by the medial neurosecretory cells of the pars intercerebralis, and in anautogenous species is stored in the corpus cardiacum until a blood-meal is taken. Removal of the head of the mosquito Aedes aegypti (L.), shortly after completion of a blood-meal, has previously been shown not only to prevent oöcyte maturation, but also to result in early elimination of the blood-meal. The work described in this paper shows that it is a factor originating in the medial neuro­-secretory cells, presumably egg development neurosecretory hormone, which is essential if the blood-meal is to be retained in the mid-gut until the oöcytes are nearing maturity.

Pathology of Coelomomyces stegomyiae in adult Aedes aegypti ovaries

1988 ◽  
Vol 66 (5) ◽  
pp. 877-884 ◽  
Author(s):  
Christopher J. Lucarotti ◽  
Marina B. Klein
Keyword(s):  
Plasma Membrane ◽  
Aedes Aegypti ◽  
Adult Female ◽  
Blood Meal ◽  
Egg Development ◽  
Yolk Granules ◽  
Receptor Mediated Endocytosis ◽  
Fungal Hyphae ◽  
Tunica Propria ◽  
Coelomomyces Stegomyiae

Coelomomyces stegomyiae (Chytridiomycetes, Blastocladiales) infection in adult female Aedes aegypti (Diptera, Culicidae) is located primarily in the ovaries. Fungal hyphae do not penetrate the germaria or follicles but instead lie between the tunica propria and epithelial sheath within each ovariole and between the epithelial sheath and the peritoneal sheath of the ovary. Aedes aegypti is an anautogenous mosquito requiring a blood meal for egg development; similarly, fungal hyphae in infected ovaries will not differentiate to form resting sporangia until after the mosquito has taken a blood meal. The fungus restricts receptor-mediated endocytosis of vitellogenin by the plasma membrane of the oocyte so that few, if any, vitellin yolk granules form. Thick-walled resting sporangia have formed 72 h after the blood meal has been taken and these will be oviposited by the females in place of the aborted eggs.

scholarly journals Hormone-dependent activation and repression of microRNAs by the ecdysone receptor in the dengue vector mosquito Aedes aegypti

2021 ◽  
Vol 118 (26) ◽  
pp. e2102417118
Author(s):  
Ya-Zhou He ◽  
Emre Aksoy ◽  
Yike Ding ◽  
Alexander S. Raikhel
Keyword(s):  
Aedes Aegypti ◽  
Mirna Expression ◽  
Blood Meal ◽  
Fat Body ◽  
Blood Feeding ◽  
Small Rna Sequencing ◽  
Sequencing Analysis ◽  
Ecdysone Receptor ◽  
Egg Development ◽  
Semialdehyde Dehydrogenase

Female mosquitoes transmit numerous devastating human diseases because they require vertebrate blood meal for egg development. MicroRNAs (miRNAs) play critical roles across multiple reproductive processes in female Aedes aegypti mosquitoes. However, how miRNAs are controlled to coordinate their activity with the demands of mosquito reproduction remains largely unknown. We report that the ecdysone receptor (EcR)–mediated 20-hydroxyecdysone (20E) signaling regulates miRNA expression in female mosquitoes. EcR RNA-interference silencing linked to small RNA-sequencing analysis reveals that EcR not only activates but also represses miRNA expression in the female mosquito fat body, a functional analog of the vertebrate liver. EcR directly represses the expression of clustered miR-275 and miR-305 before blood feeding when the 20E titer is low, whereas it activates their expression in response to the increased 20E titer after a blood meal. Furthermore, we find that SMRTER, an insect analog of the vertebrate nuclear receptor corepressors SMRT and N-CoR, interacts with EcR in a 20E-sensitive manner and is required for EcR-mediated repression of miRNA expression in Ae. aegypti mosquitoes. In addition, we demonstrate that miR-275 and miR-305 directly target glutamate semialdehyde dehydrogenase and AAEL009899, respectively, to facilitate egg development. This study reveals a mechanism for how miRNAs are controlled by the 20E signaling pathway to coordinate their activity with the demands of mosquito reproduction.

Projection of FMRFamide-like neuropeptide-producing neurosecretory cells from silkworm brain into ventral nerve cord and retrocerebral complex

2012 ◽  
Vol 144 (3) ◽  
pp. 458-466 ◽  
Author(s):  
Bo Yong Kim ◽  
Hwa Young Song ◽  
Mi Young Kim ◽  
Pil Don Kang ◽  
Min Ho Cha ◽  
...  
Keyword(s):  
Juvenile Hormone ◽  
Bombyx Mori ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Neurosecretory Cells ◽  
Single Pair ◽  
Corpus Cardiacum ◽  
Pars Intercerebralis ◽  
Median Region ◽  
The Brain

AbstractUsing immunostaining methodology, we traced the axonal projection of FMRFamide (Phe-Met-Arg-Phe-NH2)-like immunoreactive (LI) medial neurosecretory cells (MNCs) and lateral neurosecretory cells (LNCs) from the brain into the ventral nerve cord (VNC) and retrocerebral complex in Bombyx mori (L.) (Lepidoptera: Bombycidae). Of the seven pairs of FMRFamide-LI MNCs, one pair extended its axons from the brain pars intercerebralis into the VNC ipsilateral connective where they appeared to terminate. The axons of the remaining MNCs ran through decussation in the brain median region and contralateral nervi corporis cardiaci (NCC) I out of the brain, and eventually innervated the contralateral corpus cardiacum (CC). Axons from the single pair of FMRFamide-LI LNCs projected into the ipsilateral NCC II fused with NCC I without decussation in the brain, and finally terminated in the CC. These results suggest that transport of the FMRFamide-like neuropeptide from may be related to the modulation of functions such as gut contraction in MNCs terminating in the VNC, and regulation of production and/or secretion of specific hormones such as juvenile hormone in MNCs and LNCs terminating in the CC.

The influence of the brain hormone on retention of blood in the mid-gut of the mosquito Aedes aegypti (L.)

1975 ◽  
Vol 190 (1100) ◽  
pp. 359-367 ◽  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Endocrine System ◽  
Hormonal Action ◽  
Two Phases ◽  
The Brain

Development of the oöcytes after a blood-meal in the mosquito Aedes aegypti occurs in two phases: initiation , which is independent of hormonal action, and promotion to maturity, which is dependent on a neurosecretory hormone from the brain (acting through the endocrine system of the thorax). During the promotion-phase, material for the growth of the oöcytes is mobilized from the blood in the mid-gut. The work described here explores the possibility and confirms that one of the functions of the brain hormone is to retain the blood in the mid-gut until development of the oöcytes is complete.

scholarly journals ECDYSONE-MEDIATED STIMULATION OF DOPA DECARBOXYLASE ACTIVITY AND ITS RELATIONSHIP TO OVARIAN DEVELOPMENT IN AEDES AEGYPTI

1974 ◽  
Vol 61 (2) ◽  
pp. 454-465 ◽  
Author(s):  
Dorothy A. Schlaeger ◽  
Morton S. Fuchs ◽  
Suk-Hee Kang
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Ovarian Development ◽  
Blood Feeding ◽  
Dopa Decarboxylase ◽  
Decarboxylase Activity ◽  
Molting Hormone ◽  
Radioimmune Assay ◽  
Juvenile Hormone Mimic ◽  
Stimulation Of

Very little dopa decarboxylase activity is detectable in adult female mosquitoes Aedes aegypti which have not been allowed to engorge blood. However, when such females are injected with the molting hormone ß-ecdysone a marked stimulation of this enzyme's activity is observable. No stimulation is observed in males similarly injected, nor in females injected with cholesterol or a juvenile hormone mimic. In addition, ecdysone injection initiates ovarian development in these anautogenous non-blood-fed mosquitoes. The extent of stimulation in both cases is dependent upon the amount of ß-ecdysone administered. These results suggested that ecdysone may play a role in ovarian development in Aedes and led us to hypothesize that a normal blood meal may trigger the synthesis, activation, or release of this hormone endogenously. Using the radioimmune assay for ecdysone developed by Borst and O'Connor (Science [Wash. D. C.] 178:4–18.), we found that the titer of an antigenic-positive material, presumably ecdysone or a closely related analogue, substantially increased 24 h after blood feeding, thereby supporting our postulation.

QUANTITATIVE ASPECTS OF OVARIAN DEVELOPMENT IN MOSQUITOES

1971 ◽  
Vol 103 (5) ◽  
pp. 763-773 ◽  
Author(s):  
R. E. Bellamy ◽  
G. K. Bracken
Keyword(s):  
Amino Acids ◽  
Blood Meal ◽  
Culex Pipiens ◽  
Ovarian Development ◽  
Direct Injection ◽  
Ovarian Response ◽  
Egg Development ◽  
Egg Albumen ◽  
Complete Digestion

AbstractExperiments on an anautogenous strain of Culex pipiens L. failed to support the theory that sustained gut stretching initiates egg development by anautogenous mosquitoes. The stomach expanded in females fed sugar after the anus was sealed, but eggs did not develop. Also, the ovaries were not activated by an enema of agar which congealed in the stomach and kept it distended. Development of eggs by females given enemas of γ-globulin or egg albumen was presumably an ovarian response to nutrient; development of eggs by some females that received nutrient (amino acids) by direct injection into the haemocoele supported this interpretation. When 1, 4, 7, and 10% egg albumen or γ-globulin were supplied as volumetrically equal enemas, response to 1% was least (few eggs matured and these by only a few females), but was greater with increased amounts of nutrient. It is proposed that certain mechanisms permit the mosquito to evaluate the nutrient potentially available in a blood meal before its complete digestion and to start maturation of an appropriate number of eggs.

The brain structure and neurosecretory cells of noctuid moth Anadevidia peponis: Noctuidae

1990 ◽  
Vol 48 (3) ◽  
pp. 436-437
Author(s):  
M. Sato ◽  
Y. Ogawa ◽  
M. Sasaki ◽  
T. Matsuo
Keyword(s):  
Biological Clock ◽  
Virgin Female ◽  
Basic Structure ◽  
Fixed Time ◽  
Neurosecretory Cells ◽  
Nerve Cells ◽  
Noctuid Moth ◽  
The Right ◽  
20 Nm ◽  
The Brain

A virgin female of the noctuid moth, a kind of noctuidae that eats cucumis, etc. performs calling at a fixed time of each day, depending on the length of a day. The photoreceptors that induce this calling are located around the neurosecretory cells (NSC) in the central portion of the protocerebrum. Besides, it is considered that the female’s biological clock is located also in the cerebral lobe. In order to elucidate the calling and the function of the biological clock, it is necessary to clarify the basic structure of the brain. The observation results of 12 or 30 day-old noctuid moths showed that their brains are basically composed of an outer and an inner portion-neural lamella (about 2.5 μm) of collagen fibril and perineurium cells. Furthermore, nerve cells surround the cerebral lobes, in which NSCs, mushroom bodies, and central nerve cells, etc. are observed. The NSCs are large-sized (20 to 30 μm dia.) cells, which are located in the pons intercerebralis of the head section and at the rear of the mushroom body (two each on the right and left). Furthermore, the cells were classified into two types: one having many free ribosoms 15 to 20 nm in dia. and the other having granules 150 to 350 nm in dia. (Fig. 1).

HISTOMORPHOLOGICAL CHANGES IN THE BRAIN IN RELATION TO OVARIAN CYCLE OF FRESHWATER CRAB, BARYTELPHUSA CUNICULARIS

2017 ◽  
Vol 23 (1) ◽  
Author(s):  
C.A. JAWALE
Keyword(s):  
Staining Intensity ◽  
Neurosecretory Cells ◽  
Ovarian Cycle ◽  
Secretory Product ◽  
Freshwater Crab ◽  
Intensity Index ◽  
Cytoplasmic Material ◽  
Histomorphological Changes ◽  
Cyclic Changes ◽  
The Brain

Ovarian maturation by neurosecretory cells in the brain of freshwater crab, Barytelphusa cunicularis have been examined. The histological scrutiny of the brain of Barytelphusa cunicularis related with three types (A, B and C) of neurosecretory cells, which are classified on the basis of size, shape and tinctorial characters. All these types of cells marked annual cyclic changes of cytoplasmic material in association with ovarian cycle. The activity of these cells has been correlated with the ovarian cycle. They are distinguishable by their size, nature locations, shape, nucleus position, cell measure and the secretory product in the cytoplasm. The result indicates that the neurosecretory A, B and C cells of the brain seen involved in the process of mating ovulation. The neurosecretory materials staining intensity index of these cells is described.

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