Ultrastructural changes in tissues of larval Elateridae (Coleoptera) infected with the fungus Metarrhizium anisopliae

1971 ◽  
Vol 17 (2) ◽  
pp. 281-289 ◽  
Author(s):  
R. Y. Zacharuk
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Fat Body ◽  
Malpighian Tubule ◽  
Malpighian Tubules ◽  
The Other ◽  
Host Cells ◽  
Ultrastructural Changes ◽  
Host Death ◽  
Host Tissues

The ultrastructural changes that occur in the cells of the hypodermis, fat body, Malpighian tubule, midgut, ventral abdominal ganglion, and muscle during mycoses in three species of elaterid larvae infected with Metarrhizium anisopliae are described. The fungus penetrated all the above tissues before host death in most of the larvae examined. In some infected larvae, however, particularly in the smaller individuals or species, only the hypodermal and fat tissues were penetrated before death. Changes in fine structure appear in all the tissues soon after the fungus enters the hemocoel, even when no fungal growths are present near the host cells. In general, there is initially an increase in the number of lysosomes and of endoplasmic reticulum and ribosomes, followed by a vesiculation of the endoplasmic reticulum and of the cristae of the mitochondria and a progressive vacuolation of the cytoplasm. In some tissues the mitochondria increase in number before vesiculation. Glycogen granules and lipid and oil inclusions disappear rapidly during mycosis. Clear, membrane-limited vacuoles become particularly abundant in the Malpighian tubules and the midgut, suggesting increased secretion of fluids into their lumens. At or soon after death, the lysosomes disappear and all the membranous structures of the cells are disrupted, and laminated or whorled bodies of thickened membranes become numerous. Disintegration of all tissues, including muscle and nerve, was extensive in some larvae that were still capable of some sluggish movement before fixation for the study. It is suggested that the fungus incites lysosome production by the host tissues along with the other initial changes observed, and that final disintegration of the host tissues is by a process of autohistolysis.

Fine Structure of the Malpighian Tubules of the Mosquito, Culex pipiens

1971 ◽  
Vol 29 ◽  
pp. 402-403
Author(s):  
Brendan Clifford
Keyword(s):  
Fine Structure ◽  
Culex Pipiens ◽  
Stellate Cell ◽  
Malpighian Tubule ◽  
Cell Types ◽  
Instar Larva ◽  
Malpighian Tubules ◽  
Calliphora Erythrocephala ◽  
Distinct Cell ◽  
Basal Plasma

An ultrastructural investigation of the Malpighian tubules of the fourth instar larva of Culex pipiens was undertaken as part of a continuing study of the fine structure of transport epithelia.Each of the five Malpighian tubules was found to be morphologically identical and regionally undifferentiated. Two distinct cell types, the primary and stellate, were found intermingled along the length of each tubule. The ultrastructure of the stellate cell was previously described in the Malpighian tubule of the blowfly, Calliphora erythrocephala by Berridge and Oschman.The basal plasma membrane of the primary cell is extremely irregular, giving rise to a complex interconnecting network of basal channels. The compartments of cytoplasm entrapped within this system of basal infoldings contain mitochondria, free ribosomes, and small amounts of rough endoplasmic reticulum. The mitochondria are distinctive in that the cristae run parallel to the long axis of the organelle.

Amino-Acid Metabolism in Locust Tissues

1957 ◽  
Vol 34 (2) ◽  
pp. 276-289
Author(s):  
B. A. KILBY ◽  
ELISABETH NEVILLE
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Schistocerca Gregaria ◽  
Fat Body ◽  
Malpighian Tubule ◽  
Malpighian Tubules ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Mitochondrial Fractions

1. Homogenates of fat-body of Schistocerca gregaria Forsk. were shown to catalyse transamination reactions between α-ketoglutarate and numerous α-amino acids. The aspartate/glutamate and alanine/glutamate transaminases were the most active. They were present in both the ‘soluble’ and the mitochondrial fractions of fat-body cells and also in Malpighian tubules and mid-gut wall. The other transaminases in the fat-body were confined to the mitochondrial fraction. 2. Fat-body, Malpighian tubule and mid-gut wall homogenates were able to convert glutamic acid into glutamine, a compound which could also act as an amino-group donor in some transamination reactions. 3. A glutamate-cytochrome c reductase system which involved diphosphopyridine nucleotide was present in fat-body. 4. Fat-body contained an active arginase, but urease could not be detected. A D-amino-acid oxidase was present, together with a less active L-amino-acid oxidase. 5. In general, it appears that amino-acid metabolism in the locust resembles that in higher animals.

Ultrastructural changes in the cell surface of Coelomomyces punctatus infecting mosquito larvae

1976 ◽  
Vol 54 (13) ◽  
pp. 1419-1437 ◽  
Author(s):  
Martha J. Powell
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Granular Material ◽  
Fat Body ◽  
Vegetative Stage ◽  
Ultrastructural Changes ◽  
Anopheles Quadrimaculatus ◽  
Advanced Stages ◽  
Hyphal Bodies ◽  
Hyphal Body

As the fungus Coelomomyces punctatus develops in the coelomic cavity of the mosquito Anopheles quadrimaculatus, the conformation of the plasma membrane and extracellular coat of the fungus changes markedly. The vegetative stage was surrounded by a granular and fibrillar extracellular coat which reacted positively in the silver methenamine procedure for the localization of polysaccharides. Numerous simple, branched or contorted cytoplasmic protuberances covered the irregularly shaped hyphal bodies. The surface of the hyphal body adjacent to the fat body of the mosquito had occasional involutions of the plasma membrane sheathed by cisternae of endoplasmic reticulum. In contrast with these hyphal bodies, cytoplasmic protuberances were spaced at wide intervals along filamentous hyphae. Aborting thalli were contorted and deeply lobed. The plasma membrane was smooth, and cytoplasmic protuberances were absent on other hyphae and hyphal bodies, particularly at advanced stages of infection. Instead unattached vesicles, morphologically similar to the protuberances found on some thalli, were embedded in granular material clustered around the smooth plasma membrane of these thalli. Mosquito hemocytes appeared to engulf these vesicles and granular material. As the vegetative stage was transformed into the reproductive stage, a newly formed, compact extracellular layer surrounded the sporangial initial. Later, a darkly staining wall appeared around the resting sporangium. Cisternae of endoplasmic reticulum consistently subtended thin areas in this pitted wall.

Ultrastructural changes induced in zoospores of Lagenidium callinectes by exposure to Captan

1979 ◽  
Vol 57 (20) ◽  
pp. 2116-2121 ◽  
Author(s):  
D. G. Ruch ◽  
C. E. Bland
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Nuclear Matrix ◽  
Active Component ◽  
Marine Fungus ◽  
Toxic Action ◽  
Ultrastructural Changes ◽  
Mitochondrial Matrix ◽  
Growth Development

The effects of the fungicide Captan on growth, development, and fine structure of the marine fungus Lagenidium callinectes Couch are studied. At the minimum lethal concentration (LC100) of Captan for L. callinectes (3.2 ppm active component), zoospores exposed for 30 min failed to encyst or germinate. Ultrastructural changes caused by exposure to Captan included "washing-out" of the mitochondrial matrix and disappearance of many of the cristae, clumping of the chromatin and disappearance of the nuclear matrix, and swelling of the cisternae of the endoplasmic reticulum. Longer exposure of zoospores to Captan resulted ultimately in breakdown of the plasma membrane. These observations were in agreement with those of previous studies which indicated that the toxic action of Captan occurs primarily in mitochondria.

The Fine Structure of Primordial Germ Cells of the Rat

1973 ◽  
Vol 31 ◽  
pp. 634-635
Author(s):  
E. M. Eddy
Keyword(s):  
Endoplasmic Reticulum ◽  
Life History ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Germ Cells ◽  
Fibrous Material ◽  
Primordial Germ Cells ◽  
The Other ◽  
Large Size ◽  
History Of

Primordial germ cells are readily recognizable in embryos of the rat due to their large size, generally rounded shape and prominent nuclei with uniformly dispersed heterochromatin. They often have blunted pseudopodal processes at one end and small ruffles or trailing processes at the other, characteristics expected from their known ameboid activity- and migratory abilities. Also, the cytoplasm is rich in polyribosomes and contains a modest amount of rough endoplasmic reticulum and the mitochondria are frequently larger and less dense than those of adjacent somatic cells.In addition to these general characteristics, there are features unique to germ cells which allow them to be identified with certainty. These are: 1) small vesicles containing an irregular, dense core and 2) discrete accumulations of fibrous material known as nuage. Both of these features are present in other species and at other times in the life history of germ cells. The dense-cored vesicles have been noted in fetal and early postnatal mouse oogonia and oocytes, and in hamster and rabbit oocytes.

The fine structure of the developing macrogamete of Eimeria maxima

Parasitology ◽  
1979 ◽  
Vol 79 (2) ◽  
pp. 259-265 ◽  
Author(s):  
R. M. Pittilo ◽  
S. J. Ball
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Parasitophorous Vacuole ◽  
The Other ◽  
Granular Endoplasmic Reticulum ◽  
Type I ◽  
Type Ii ◽  
Eimeria Maxima ◽  
Lipid Inclusions

SUMMARYThe fine structure of the developing macrogamete of Eimeria maxima was studied from chicks killed at intervals from 138 to 147 h after inoculation. The macrogamete developed within a parasitophorous vacuole. Lying within this vacuole and extending for some distance around the periphery of the macrogamete were intravacuolar tubules, grouped in certain areas, and in some cases they were seen to make direct connexions with the cytoplasm of the parasite. During development, electron-pale vesicles were pinched off externally from the surface of the macrogamete. There appeared to be 2 forms of wall-forming bodies of the Type I during development, one form being less osmiophilic than the other. Other organelles present, such as wall-forming bodies of Type II, granular endoplasmic reticulum, mitochondria, canaliculi, lipid inclusions and intravacuolar folds, were similar in structure to those of other Eimeria species.

scholarly journals UNE FORME MICROTUBULAIRE ET PARACRISTALLINE DE RETICULUM ENDOPLASMIQUE DANS LES PHOTOCYTES DES ANNELIDES POLYNOINÆ

1966 ◽  
Vol 31 (1) ◽  
pp. 135-158 ◽  
Author(s):  
J. M. Bassot
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Nuclear Envelope ◽  
Contact Surface ◽  
Special Kind ◽  
The Other ◽  
Cytoplasmic Organelle ◽  
Specialized Form

Luminous cells of polynoid worm elytra have been examined by methods of electron microscopy, with special attention focused on the fine structure of photogenic grains. These cells send apical prolongations into the mid-part of the elytra. The plasma membrane is very sinuous, and a special kind of desmosome links two portions of the same membrane. In addition to all the organelles which can be found in nonluminescent epithelial cells of the elytra, numerous photogenic grains are contained in their cytoplasm. These grains are composed of undulating microtubules measuring 200 A in diameter; their disposition in the grain is highly regular, and the grains appear as paracrystals. At the borders of the grains, the walls of the microtubules are often in continuity with those of the endoplasmic reticulum and with the external membrane of the nuclear envelope. Because of this fact, the microtubules of the grains may be considered a cytoplasmic organelle, representing a specialized form of the endoplasmic reticulum. The microtubules permit the repartition, inside and outside their walls, of two different products, one being forty-three times more abundant than the other; thus, the contact surface, in comparison to the volume, is greatly increased. The induction of the luminous reaction by change in the permeability of the microtubule walls, allowing contact between the two substances, is suggested as a working hypothesis. There is an evolution of the grains along the axis of the photocytes. The grains are often surrounded by progressively increasing amounts of glycogen. Their paracrystalline disposition is altered at the apex of the luminous cells.

Fine structure of compound eyes of cicindela tranquebarica herbst (coleoptera: cicindelidae)

1978 ◽  
Vol 36 (2) ◽  
pp. 604-605
Author(s):  
Janice E. Kuster
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Cell Nucleus ◽  
The Other ◽  
Pigment Cells ◽  
Compound Eyes ◽  
Basal Bodies ◽  
Protein Deposits ◽  
Corneal Lens

The fine structure of photopic eucone eyes of Cicindela tranquebarica adults was examined using cryofracture SEM, TEM, and freeze-etch techniques. A “subcorneal layer” can be distinguished between the corneal lens and crystalline cone. In surface view (Fig. 1) this layer consists of concave polygons (po). It has parabolic lamellae (lm) of endocuticle consisting of microfibrils (mf) having a chitin core with protein deposits along their lengths (Fig. 2). Two primary pigment cells (lp) are devoid of pigment granules, but are rich in rough endoplasmic reticulum (rer) and surround a crystalline thread (ct) (Fig. 3). Extensions of the crystalline thread form inter-retinular fibers (f) containing microtubules between retinula cells 1/2, 3/4, 5/6, and 7/1 (Figs. 4, 5).Distal to each retinula cell nucleus are two basal bodies (bb), one perpendicular to the other (Fig. 4). The proximal body extends two fibrillar feet which fuse to form a horizontally banded ciliary rootlet which extends the retinula length peripheral to the rhabdom.

Memoirs: Observations on the Embryology of Corynodes Pusis (Coleoptera, Chrysomelidae)

1935 ◽  
Vol s2-78 (309) ◽  
pp. 91-131
Author(s):  
NELLIE F. PATERSON
Keyword(s):  
Fat Body ◽  
Lower Layer ◽  
Muscle Layer ◽  
Posterior Pole ◽  
Malpighian Tubules ◽  
The Other ◽  
Epithelial Layer ◽  
Insect Embryos ◽  
Lateral Mesoderm ◽  
Asclepias Fruticosa

An account is given of the embryology of Corynodes pusis Marsh, a Chrysomelid beetle feeding on Asclepias fruticosa. The development of this species is remarkably similar to that of Euryope terminalis, an allied species previously investigated by the writer (1931, 1932). In both species there is a very early differentiation of the germinal protoplasm at the posterior pole, and the genital rudiment makes its appearance in this position immediately the blastoderm is completed. The lower layer of cells is derived by proliferation and invagination of cells in the mid-ventral line, and this process is considered to represent the gastrulation phase of other invertebrate embryos. The cells resulting from this invagination differentiate into lateral mesoderm and median endoderm. The mesoderm gives rise to appendicular and segmental muscles, fat-body, cardioblasts, and the muscle-layer of the mesenteron. The epithelial layer of the mid-gut is considered to develop from the median endoderm, which gives no indication in either of these species of a bipolar condition. In this respect the development of these two species differs from that of other recently investigated insects, but shows some resemblance to the condition described by Leuzinger and Wiesmann (1926) in the Orthopteran, Carausius morosus. The development of the ectoderm is essentially similar to that of other insect embryos. The stomodaeum and proctodaeum are imaginations of the ectoderm, as are also the respiratory and excretory systems. In addition to the two pairs of thoracic and eight pairs of abdominal spiracles observed in Euryope, there are vestigial spiracular invaginations on the ninth and tenth abdominal segments of Corynodes. In both species the Malpighian tubules arise as three separate pairs of outgrowths of the wall of the proctodaeum, and there is no indication that any part of their wall is derived from the endoderm, an opinion recently expressed by Henson (1932) when describing the condition in the embryo of Pieris. The tentorium is rather better developed in Corynodes than in Euryope, and in the embryo four pairs of cephalic ectodermal invaginations were observed to arise in a series one behind the other on the antennary, mandibular, maxillary, and labial segments.

Transcellular and Paracellular Flow of Water During Secretion in the Upper Segment of the Malpighian Tubule of Rhodnius Prolixus: Solvent Drag of Molecules of Graded Size

1986 ◽  
Vol 123 (1) ◽  
pp. 71-92
Author(s):  
GUILLERMO WHITTEMBURY ◽  
ANGELA C. BIONDI ◽  
AZAEL PAZ-ALIAGA ◽  
HENRY LINARES ◽  
VALENTÍN PARTHE ◽  
...  
Keyword(s):  
Extracellular Space ◽  
Malpighian Tubule ◽  
Volume Flow ◽  
Malpighian Tubules ◽  
The Other ◽  
Solvent Drag ◽  
Water Flows ◽  
Relative Contribution ◽  
Paracellular Flow ◽  
Diffusive Component

The following molecules graded in size were added to the fluid bathing the blind end of the upper segment of the Malpighian tubules of Rhodnius: urea (U), erythritol (E), mannitol (M), L-glucose (G), sucrose (S), polyethyleneglycol 800 (PEG), raffinose (R), inulin (I) and dextran 15000–18000 (D). U, E, M and G distribute themselves within the cell and the extracellular space, while S, PEG, R, I and D are exclusively extracellular. In addition, the net secretory flow (Jnm8) of these probes was studied as a function of the net secretory volume flow (Jv). Jn8, is made up of a diffusive component (Jd8), mainly due to unstirred layer effects, and of a convective component (Jc8), due to the drag (entrainment) of the probes by the water flow. The relative contribution of Jd8 and of Jc8 for each probe was studied as a function of Jv. It was found that Jc8 >> Jd8 for U, E, M, G, S and PEG. Therefore these probes are dragged by water. On the other hand Jd8 = Jn8 for R, I and D, which are not entrained. It is concluded that water flows via extracellular pathways since S and PEG, which are true extracellular probes, are entrained by solvent. In addition to extracellular pathways, it is suggested that the transcellular structures described by Wessing (1965) and Bergeron et al. (1985) could also be the sites of solute-solvent coupling

Sign in / Sign up

Export Citation Format

Share Document