The Deposition of the Third Instar Larval Cuticle of Calliphora erythrocephala

1954 ◽  
Vol s3-95 (29) ◽  
pp. 49-66
Author(s):  
L. S. WOLFE
Keyword(s):  
Secretory Granules ◽  
Histological Study ◽  
Epidermal Cells ◽  
Secretory Cycle ◽  
Calliphora Erythrocephala ◽  
The Third ◽  
Dermal Glands ◽  
Phenolic Substances ◽  
Pore Canals ◽  
Cytoplasmic Processes

A histological study has been made of the formation of the cuticle of the third instar of Calliphora. Increase in size of the epidermal cells and nuclei, particularly in the spiny regions, preceded the release of the moulting fluid. The cytoplasm first became vacuolated and this was followed by the appearance of many granules. The basement membrane is constituted in part by stellate tracheoblast cells. The membrane breaks down just before cuticle deposition and reappears after ecdysis. The outer epicuticle is formed from coalesced droplets aligned at the cell surface to form a delicate continuous, folded, acidophil, lipoprotein layer. Further, protein and lipoid (cuticulin) is added beneath this layer from cytoplasmic processes to form the inner epicuticle. These processes later became the pore canals. Endocuticle is secreted as filaments from the epidermal cells between and around the processes. During moulting, phenolic substances and oxidase are transported to the inner epicuticle only in the cuticular spines. Wax and cement layers are not formed and there are no dermal glands. The peak in the secretory cycle of the oenocytes corresponds to the time of deposition of the epicuticle and the secretory material shows similar staining properties to epicuticular material. The oenocyte groups are connected with each other and with the epidermis by cytoplasmic extensions, through which secretory granules pass. The muscle insertions are not attacked by the moulting fluid. They are thought to contain protein-bound sulphur. The separation of the muscle insertions and sensory organs from the exuvial cuticle occurs just before ecdysis. The nature of the epicuticle and the theory that the oenocytes are associated with its formation is discussed.

Further Studies of the Third Instar Larval Cuticle of Calliphora erythrocephala

1955 ◽  
Vol s3-96 (34) ◽  
pp. 181-191
Author(s):  
L. S. WOLFE
Keyword(s):  
Nitrate Solution ◽  
Silver Nitrate Solution ◽  
Instar Larva ◽  
Secretory Cycle ◽  
Calliphora Erythrocephala ◽  
The Third ◽  
Puparium Formation ◽  
Pore Canals ◽  
Third Instar Larva ◽  
Ammoniacal Silver

The penetration and reduction of ammoniacal silver nitrate solution in the epicuticle of the larva of Calliphora was studied. The epicuticle of the third instar larva is more permeable over the muscle insertions and cuticular sense organs. This finding is related to their development at the previous moult. A surface layer of orientated wax is not present. Proteinaceous and fatty materials from the feeding medium modify the properties of the cuticle surface. Chloroformmethanol extracts a soft light brown acidic lipide from the protein of the epicuticle after contaminants from the medium are removed. The water loss from larvae and puparia of different ages and after various treatments was studied. Young puparia recover from abrasion but larvae do not. An hypothesis that waxy substances are liberated on to the surface of the puparium during hardening and darkening of the cuticle is presented and discussed. The pore canals penetrate the endocuticle until they are cut off from the epidermis by the development of the prepupal cuticle just after the puparial contraction. An inner endocuticle in which pore canals were absent was not found. The structure of the pore canals as shown by phase contrast examination is discussed. The pore canals are three times more concentrated in the lateral regions than in the dorsal or ventral regions. The oenocytes go through a secretory cycle during puparium formation similar to that occurring before moulting of the larva.

The Structure and Deposition of the Cuticle in the Adult Mealworm, Tenebrio Molitor L. (Coleoptera)

1948 ◽  
Vol s3-89 (6) ◽  
pp. 197-216
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
The Other ◽  
Secretory Cycle ◽  
Continuous Layer ◽  
Cement Layer ◽  
Dermal Glands ◽  
Basic Layer ◽  
Insoluble Form ◽  
The One ◽  
Pore Canals ◽  
Ammoniacal Silver

The conclusions on the structure of the cuticle in Tenebrio have been summarized on p. 204. Observations on the deposition of the cuticle are in general agreement with those made on Rhodnius. Mitosis and chromatolysis precede the formation of the definitive epidermis. The basic layer of the epicuticle, ‘cuticulin’, is then laid down. It consists of condensed lipoproteins (subsequently tanned, it is supposed, by quinones) and its deposition is immediately preceded by the peak in the secretory cycle of the subepidermal oenocytes. Pore canals from the epidermal cells penetrate the cuticulin layer and pour out silver-reducing material (believed to be dihydroxyphenols in insoluble form) upon its surface. This material is confined to the areas overlying the cell bodies during all but the last stages in its formation, when it fuses to give a more or less continuous layer. During the last few hours before moulting a wax layer appears to be laid down over this polyphenol layer. By the time moulting occurs the polyphenol layer is almost covered and the insect is nearly waterproof. During the first day after moulting, while the secretion of the wax is being completed, the loss of water by transpiration is about four to six times the normal. Very soon after moulting the dermal glands discharge the cement layer over the surface of the wax. The substance of this layer and the contents of the dermal glands reduce ammoniacal silver after extraction with boiling chloroform. It is suggested that it consists of polyphenol-containing material associated with protein and lipides. (It is shown that in Rhodnius the cement layer is formed by the admixture of secretion from the two types of dermal gland previously described. The one produces a solution of protein, the secretion of the other agrees in properties with that here described in Tenebrio. The similarity of this arrangement to that discovered by Pryor in the colleterial glands of the cockroach is pointed out.) In addition to these cement glands there are glands of unknown function opening into the floor of the pits in the cuticle. These are highly developed in the sternites of the male, small and inconspicuous in the female.

scholarly journals The epicuticle in an insect, Rhodnius prolixus (Hemiptera)

1947 ◽  
Vol 134 (875) ◽  
pp. 163-181 ◽  
Keyword(s):  
Rhodnius Prolixus ◽  
Epidermal Cells ◽  
Continuous Film ◽  
Cement Layer ◽  
Dermal Glands ◽  
Pore Canals

The ʻepicuticle’ in Rhodnius consists of four layers. From within outwards these are: (i) the ‘cuticulin layer’ composed, it is suggested, of polymerized lipoproteins tanned by quinones; (ii) the ‘polyphenol layer’ rich in dihydroxyphenols; (iii) the ‘wax layer’ responsible for the waterproofing of the cuticle; (iv) the ‘cement layer’ of unknown nature protecting the wax. The pore canals appear to penetrate the cuticulin layer. The oenocytes produce the lipoproteins which are deposited by the epidermal cells to form the cuticulin layer. The polyphenols then appear at the tips of the pore canals as minute droplets which unite to form a continuous film over the surface of the cuticulin. The wax is then secreted, also by the epidermal cells, and laid down over the polyphenol layer immediately before the old skin is shed. The cement is secreted by the dermal glands and poured out over the surface of the wax within an hour after moulting. The storage and use of the reserves of glycogen, fat and protein during the moulting process are described.

Transpiration and the Structure of the Epicuticle in Ticks

1947 ◽  
Vol 23 (3-4) ◽  
pp. 379-410 ◽  
Author(s):  
A. D. LEES
Keyword(s):  
Critical Temperature ◽  
Superficial Layer ◽  
Epidermal Cells ◽  
Ecological Niches ◽  
Moist Air ◽  
Critical Temperatures ◽  
Dermal Glands ◽  
Natural Choice ◽  
Pore Canals ◽  
Dual Mechanism

1. Ticks owe their impermeability primarily to a superficial layer of wax in the epicuticle. After exposure to increasing temperatures, water loss increases abruptly at a certain ‘critical temperature’. The critical temperature varies widely in different species, in Ixodidae ranging from 32 (Ixodes ricinus) to 45° C. (Hyalomma savignyi); and in Argasidae from 63 (Ornithodorus moubata) to 75° C. (O. savignyi). Species having higher critical temperatures are more resistant to desiccation at temperatures within the biological range. A broad correlation is possible between these powers of resistance and the natural choice of habitat. Argasidae infest dry, dusty situations whereas Ixodidae occupy a much wider variety of ‘ecological niches’. 2. If the tick cuticle is rubbed with abrasive dust, evaporation is enormously increased. Living ticks partially restore their impermeability in moist air by secreting wax from the pore canals on to the surface of the damaged cuticle. 3. Unfed ticks are able to take up water rapidly through the wax layer when exposed to high humidities. Water uptake, which is dependent on the secretory activities of the epidermal cells, is completely inhibited by the abrasion of only part of the total cuticle surface--a fact which suggests that the cells are functionally interconnected. Resistance to desiccation at low humidities is achieved by a dual mechanism: active secretion and the physical retention of water by the wax layer. 4. In Argasidae the epicuticle consists of four layers: the cuticulin, polyphenol, wax and outer cement layers. Only the three inner layers are present in Ixodidae. Since the wax layer is freely exposed in the latter group, chloroform and detergents have a marked action in increasing transpiration, particularly in those species with low critical temperatures. In Argasidae the cement layer is very resistant to extraction but is broken down by boiling chloroform. 5. The cuticulin, polyphenol and wax layers are all secreted by the epidermal cells. The waterproofing layer, which is deposited on the completed polyphenol layer, is secreted by the moulting tick relatively early in development and may be nearly complete by the time moulting fluid is abundant. In Ornithodorus moubata the cement is poured out by the dermal glands shortly after emergence. In Ixodidae the dermal glands undergo a complex cycle of growth and degeneration, but their products appear to add nothing of functional significance to the substance of the cuticle.

The Outer Layers of the Cuticle in the Cockroach Periplaneta americana and the Function of the Oenocytes

1950 ◽  
Vol s3-91 (13) ◽  
pp. 63-72 ◽  
Author(s):  
S. KRAMER ◽  
V. B. WIGGLESWORTH
Keyword(s):  
Honey Bee ◽  
Periplaneta Americana ◽  
Epidermal Cells ◽  
Cuticular Wax ◽  
Cement Layer ◽  
Dermal Glands ◽  
Protein Components ◽  
Egg Shell ◽  
Pore Canals

In the epicuticle of the cockroach there is a cement layer formed, as in other insects, by secretion from certain of the dermal glands at the time of moulting. These dermal glands are widely distributed over the abdominal tergites and sternites in both sexes. Their cell-bodies are atrophied in the mature insect. They differ in this respect from the very numerous dermal glands on the abdominal tergites of the male, which remain distended with vacuoles. The cuticular wax, which is freely exposed on the surface of the cuticle, is thought to be produced by the sub-epidermal oenocytes and to be discharged during the life of the cockroach, perhaps through the pore canals, by the epidermal cells. The oenocytes of the honey-bee are much larger during the height of wax secretion than they are in the foraging bee. The view that the oenocytes are concerned in wax metabolism is compatible with the view that they synthesize the lipoprotein (or wax protein) components of the cuticle and egg-shell.

Distribution of lipid in the lamellate endocuticle of Rhodnius prolixus (Hemiptera)

1975 ◽  
Vol 19 (3) ◽  
pp. 439-457
Author(s):  
V.B. Wigglesworth
Keyword(s):  
Cross Section ◽  
Lipid Fraction ◽  
Rhodnius Prolixus ◽  
Epidermal Cells ◽  
Cyclical Change ◽  
Apocrine Secretion ◽  
Pore Canals ◽  
Lipid Layers

The lamellate appearance of the cuticle in the abdomen of the Rhodnius larva conforms to the conception of Bouligand in being an optical artifact which results from the spiral arrangement of successive layers of oriented fibrils. But superimposed on this structure is an actual lamination of bound lipid with the same spacing. The relation of the lipid layers to the optical lamination changes with the aspect from which the system is viewed. There must therefore be a cyclical secretion of lipid by the epidermal cells. Since the period of this cycle agrees with the cycle of rotation of the fibrous layers, which is supposedly inherent in the chemistry of the system, it is possible that it is the lipid which controls or initiates this helicoidal ‘cholesteric crystallization’. There is evidence of a cyclical change in the secretion of lipid by the microvilli; it is suggested that there may be alternating cycles of eccrine and apocrine secretion, and that the lipid laminae represent the apocrine phases. The pore canals in Rhodnius are roughly cylindrical in cross-section, with lipid-impregnated walls. The contents of the lumen become slightly more electron opaque before the cuticle is stretched by feeding. There is probably some enzymic dissolution of the cuticle which precedes stretching; and this may concern particularly the lipid fraction. After the great distension and expansion of the cuticle which occur at feeding, lipid laminae can no longer be demonstrated in the old cuticle.

Morphogenèse de l'épiderme imaginal de l'abdomen de Calliphora erythrocephala (Insecte, Diptère)

Development ◽  
1978 ◽  
Vol 43 (1) ◽  
pp. 247-261
Author(s):  
Par Anne-Marie Bautz
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Rough Endoplasmic Reticulum ◽  
Cellular Proliferation ◽  
Epidermal Cells ◽  
Sensory Cells ◽  
Calliphora Erythrocephala ◽  
Abdominal Surface ◽  
Intense Activity

The morphogenesis of the abdominal epidermis in Calliphora erythrocephala begins by a cellular proliferation which proceeds slowly in larvae and rapidly in pupae. This allows histoblasts to glide and invade the whole abdominal surface. As soon as the new epidermal sheet has become continuous, differentiation begins. Generalized epidermal cells show an intense activity which leads to the deposition of imaginal cuticle from the 6th day after pupation onwards. After cuticle deposition they darken and become inactive although they remain alive, even after emergence. Trichogen and tormogen cells are even more active than generalized epidermal cells, especially the trichogen cell in which polyribosomes and microtubules are abundant. The former are possibly involved in microtubule synthesis. After cuticle deposition the trichogen and tormogen cells undergo degeneration. Their nuclei contract, rough endoplasmic reticulum breaks down and cytoplasm breaks up into fragments through infoldings which proliferate from the plasma membrane. Finally only generalized epidermal cells and sensory cells remain alive in the adult.

The Cuticle of Peripatopsis Moseleyi

1964 ◽  
Vol s3-105 (71) ◽  
pp. 281-299
Author(s):  
ELAINE A. ROBSON
Keyword(s):  
Body Wall ◽  
Light And Electron Microscopy ◽  
Thick Layer ◽  
The Body ◽  
Muscle Fibres ◽  
Terrestrial Arthropods ◽  
Dermal Glands ◽  
Arthropod Cuticle ◽  
Primitive Condition ◽  
Pore Canals

The integument of Peripatopsis moseleyi has been examined by light and electron microscopy with particular reference to the structure and formation of the cuticle. The evidence supports the idea that Peripatus is a true arthropod but not that it has direct affinities with the annelids. The characteristics of arthropod cuticle are present in their simplest form and pore canals and dermal glands are lacking. The cuticle is 1 or 2 µ, thick except in the hardened claws and spines. Above the procuticle (chitinprotein) is a thin 4-layered epicuticle. It is possible that the innermost of the 4 layers (prosclerotin) may correspond to cuticulin of other arthropods. In the claws and spines tanning in this layer extends to the procuticle. Hydrofuge properties of the cuticle probably depend on the outer layers of epicuticle, and it is suggested that the lamina concerned might consist of oriented lipid associated with lipoprotein (Dr. J. W. L. Beament). Wax and cement are absent. Non-wettability of the cuticle is probably ensured by the contours of micropapillae which cover the surface. Similar structures arise in Collembola and other terrestrial arthropods by convergence. The formation of new cuticle before ecdysis is described. After the epicuticular layers are complete, the bulk of the procuticle is laid down in a manner probably common to all arthropods. Secreted materials originate in small vesicles derived from rough endoplasmic reticulum and from scattered Golgi regions. The latter contribute to larger vacuoles which rise to the surface of the cell and liberate material in a fluid state. This later consolidates to form procuticle. Vesicles may also open to the surface directly, and ribosomes probably occur free in the cytoplasm. At this stage the cell surface is reticulate, especially under micropapillae. The ordinary epidermis has only one kind of cell, attached to the cuticle by tonofibrils disposed like the ribs of a shuttlecock, and to the fibrous sheaths of underlying muscle-fibres by special fibres of connective tissue. These features and the presence of numerous sensory papillae are associated with the characteristic mobility of the body wall. The appearance of epidermal pigment granules, mitochondria, the nuclear membrane, and a centriole are noted. No other cells immediately concerned in the formation of cuticle have been found. By contrast myriapods, which do not have wax either, possess dermal glands secreting far more lipid than is found in the Onychophora. The wax layer found in insects and some arachnids constitutes an advance of high selective value which emphasizes the primitive condition of the Onychophora. It is noted that the thick layer of collagen separating the haemocoel from the epidermis probably restricts the transfer of materials. It is suggested that since some features of cuticular structure and formation appear to be common to all arthropods, it is possible that some of the endocrine mechanisms associated with ecdysis may also be similar throughout the phylum.

scholarly journals STRUCTURE AND DEVELOPMENT OF VIRUSES AS OBSERVED IN THE ELECTRON MICROSCOPE

1962 ◽  
Vol 116 (4) ◽  
pp. 553-564 ◽  
Author(s):  
Councilman Morgan ◽  
Konrad C. Hsu ◽  
Harry M. Rose
Keyword(s):  
Influenza Virus ◽  
Viral Antigen ◽  
Electron Microscopic Examination ◽  
Serial Passage ◽  
Electron Microscopic ◽  
The Third ◽  
Magnus Effect ◽  
Viral Particles ◽  
Membrane Bound ◽  
Cytoplasmic Processes

Chicken embryos were infected by the chorioallantoic route with influenza virus, PR8 strain, in the form of undiluted chorioallantoic fluid. Electron microscopic examination 24 hours after infection revealed that membrane-bound fragments of cytoplasm appeared to be in process of release from entodermal cells of the chorioallantois. The number of such fragments was greatly increased in proportion to the number of typical viral particles after the third serial passage, which was accompanied by a reduction of the infectivity-hemagglutinin ratio (von Magnus effect). The lack of recognizable internal components, together with the presence of surface structure which closely resembled that of the virus and frequently contained viral antigen, suggested that many of these fragments were incomplete viral particles. It is proposed that concentrated inocula damage the cells and interfere with differentiation of the virus, but do not inhibit formation and detachment of cytoplasmic processes. Under these circumstances the accumulation of viral antigen at the surface of the cell will result in the predominant formation of incomplete virus.

Sign in / Sign up

Export Citation Format

Share Document