Compound sensilla in monogenean skin parasites

The fine structure of two kinds of compound presumed sense organs from the heads of three skin parasitic monogeneans Gyrodactylus sp. Entobdella soleae (larva only) and Acanthocotyle elegans is described. One kind of compound receptor consists of a number of associated sensilla, each ending in a single cilium (the spike sensilla of Gyrodactylus and the cone sensilla of E. soleae oncomiracidium).The other kind of compound organ is made up of one or a few neurones only, each of which bears many cilia (pit organs of E. soleae oncomiracidium and feeding organ sensilla of Acanthocotyle elegans). The spike sensilla of Gyrodactylus have also been studied using a Cambridge Instrument Co. Stereoscan electron microscope and by phase-contrast microscopy. The ciliary endings of all these sense organs are highly modified and have lost the 9 + 2 structure, being packed with many fibres. The fibre arrangement in the cilia of the cone sensillae of E. soleae oncomiracidium and the feeding organ sensilla of A. elegans has been compared with that in the ciliary endings of other invertebrate mechano- and chemoreceptors. The possibility that the spike sensilla of Gyrodactylus may be chemoreceptors has been discussed but it is considered premature to attempt to assign functions to the other sense organs studied. Electron dense membrane-bound inclusions occurring specifically in the nerves supplying the spike sensilla of Gyrodactylus may be neurosecretory.

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STUDIES ON THE MODE OF ACTION OF EXCESS OF VITAMIN A

The Journal of Cell Biology ◽

10.1083/jcb.17.1.111 ◽

1963 ◽

Vol 17 (1) ◽

pp. 111-121 ◽

Cited By ~ 48

Author(s):

Audrey M. Glauert ◽

Mary R. Daniel ◽

J. A. Lucy ◽

J. T. Dingle

Keyword(s):

Electron Microscopy ◽

Fine Structure ◽

Vitamin A ◽

Phase Contrast ◽

Phase Contrast Microscopy ◽

Intact Cells ◽

Thin Sections ◽

Initial Effect ◽

Contrast Microscopy ◽

Site Of Action

Rabbit erythrocytes have been haemolysed by treatment with vitamin A alcohol and the sequence of changes in the fine structure of the cells during lysis has been investigated by phase contrast microscopy of intact cells and electron microscopy of thin sections. The initial effect of the vitamin, which occurs within 1 minute, is the production of cells of bizarre appearance which have a greatly increased surface area relative to untreated cells. Large indentations appear in the surfaces of the cells, and vacuoles are formed from the indentations by a process that resembles micropinocytosis. The cells then become spherical and loss of haemoglobin begins as breaks appear in the membranes of some cells; finally, ghosts are produced that are no longer spherical but still contain numerous vacuoles. These observations support the thesis that one site of action of vitamin A is at lipoprotein membranes.

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Description of the immatures of the predaceous midge Bezzia blantoni Spinelli & Wirth (Diptera: Ceratopogonidae)

Zootaxa ◽

10.11646/zootaxa.2295.1.5 ◽

2009 ◽

Vol 2295 (1) ◽

pp. 46-54 ◽

Cited By ~ 3

Author(s):

MARIA M. RONDEROS ◽

GUSTAVO R. SPINELLI

Keyword(s):

Electron Microscope ◽

Phase Contrast ◽

Instar Larva ◽

Fourth Instar ◽

Phase Contrast Microscopy ◽

Fourth Instar Larva ◽

Contrast Microscopy ◽

Breeding Location ◽

First Time ◽

Scanning Electron

The fourth instar larva and pupa of Bezzia blantoni Spinelli & Wirth (1989) are described, illustrated and photomicrographed by using phase-contrast microscopy and Scanning Electron Microscope (SEM). The larva, which shows features typical to carnivorous larvae, is compared with that of B. roldani Spinelli & Wirth. The species is recorded for the first time from the Martín García island, located in the La Plata river between Argentina and Uruguay. Details of the biology traits, breeding location and feeding behavior are given.

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Sense organs of monogenean skin parasites ending in a typical cilium

Parasitology ◽

10.1017/s0031182000031152 ◽

1969 ◽

Vol 59 (3) ◽

pp. 611-623 ◽

Cited By ~ 44

Author(s):

Kathleen M. Lyons

Keyword(s):

Electron Microscope ◽

Phase Contrast ◽

Research Council ◽

Sense Organ ◽

Science Research ◽

Sense Organs ◽

Marine Biological Laboratory ◽

Sensory Neurone ◽

Research Fellowship ◽

Contrast Microscopy

Single receptors seen with the electron microscope to consist of a terminal cilium embedded in a nerve bulb have been found in the skin parasitic monogenean Gyrodactylus sp., adult and larval Entobdella soleae, Leptocotyle minor (adult) and in the endoparasitic juvenile of Amphibdella flaviolineata. Their distribution in Gyrodactylus sp. has been mapped using phase-contrast microscopy, and staining with the indoxyl acetate method for non-specific esterases revealed a nervous connexion between the lateral ventral nerve cord and the ‘tangoreceptor’. The general relationships of the nervous system in Gyrodactylus were investigated by staining with the thiocholine method for cholinesterase. The ‘sensory’ neurone contains vesicles, microtubules and mitochondria and the whole nerve bulb is sealed into the epidermis by means of septate desmosomes. The basal body of the cilium is not greatly modified and there is no obvious rootlet system. The terminal cilium of single receptors in Entobdella soleae has a 9 + 2 structure. A compound sense organ from the head of Entobdella soleae has also been described. The significance of the fibre arrangement in the terminal cilia and the possible roles of these sense organs have been discussed.I should like to thank Dr D. L. Lee for training in electron microscope techniques and for his encouragement, Dr P. Tate for his continued interest and the staff of the Marine Biological Laboratory, Plymouth, especially Mr G. Best and Mr J. E. Green, for their assistance. This work was conducted during tenure of a Science Research Council Fellowship and the Tucker-Price Research Fellowship of Girton College.

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Action of Factor XIII on Transamidation Bounds between the Collagen Molecule Constituents

10.1055/s-0039-1689317 ◽

1975 ◽

Author(s):

J. Soria ◽

G. Soria ◽

G. Boulard

Keyword(s):

Molecular Weight ◽

Gel Electrophoresis ◽

Factor Xiii ◽

Phase Contrast ◽

Polyacrylamide Gel Electrophoresis ◽

The Other ◽

Polymerization Process ◽

Collagen Molecule ◽

Phase Contrast Microscopy ◽

Contrast Microscopy

By polyacrylamide gel electrophoresis in the presence of SDS we observed that collagen polymerized in the presence of factor XIII a, is dissociated by urea into sub-units with a higher molecular weight than that polymerized in the absence of factor XIII.In the other hand, by phase contrast microscopy we have found that the structure of collagen is quite different when the polymerization process takes place in the presence or in the absence of activated factor XIII.This modification of collagen polymerization in the presence of factor XIII a possibly acts in wound healing.

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Counting dead spermatozoa in frozen semen

Animal Science ◽

10.1017/s0003356100022285 ◽

1965 ◽

Vol 7 (1) ◽

pp. 59-65 ◽

Cited By ~ 5

Author(s):

H. R. L. Buttle ◽

J. L. Hancock ◽

A. F. Purser

Keyword(s):

Analysis Of Variance ◽

Sodium Fluoride ◽

Phase Contrast ◽

Egg Yolk ◽

The Other ◽

Phase Method ◽

Phase Contrast Microscopy ◽

Frozen Semen ◽

Contrast Microscopy ◽

Differential Counts

SUMMARYThree methods were used to make differential counts of living and dead bull spermatozoa in samples of frozen semen in an egg-yolk citrate medium containing glycerol.With two methods (‘phase’ and ‘nigrosin’ methods) dead spermatozoa were identified by their altered structure. With a third method (nigrosineosin) dead spermatozoa were identified by their staining affinity. With the phase method spermatozoa were immobilised by treatment with approximately M/40 sodium fluoride and were examined by phase-contrast microscopy in unfixed wet preparations. With the other two methods the spermatozoa were examined in smears stained either with nigrosin alone (nigrosin method) or with nigrosin and eosin (nigrosin-eosin method).Analysis of variance of the results of a factorial experiment involving fluoride-treated and untreated samples from 6 bulls with the three methods showed that differences between semen samples contributed 66% of the variation. A defect of the phase method was that the variance between counts was greater than the theoretically expected value.All spermatozoa in nigrosin-eosin stained preparations were stained with eosin within a few days of the smears being made, so that living and dead spermatozoa could not be distinguished by their differing affinities for eosin. Repeat counts on nigrosin-stained preparations did not differ significantly from counts made several days previously. Sodium fluoride in the concentration used here (M/40) tended to reduce the percentage of dead spermatozoa.

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THE CYTOLOGY OF RICKETTSIAE

Journal of Experimental Medicine ◽

10.1084/jem.89.6.681 ◽

1949 ◽

Vol 89 (6) ◽

pp. 681-686 ◽

Cited By ~ 12

Author(s):

Hans Ris ◽

John P. Fox

Keyword(s):

Electron Microscope ◽

Phase Contrast ◽

Phase Contrast Microscopy ◽

Cellular Organization ◽

Desoxyribonucleic Acid ◽

Internal Structures ◽

Basic Dyes ◽

Contrast Microscopy ◽

Nuclear Structures ◽

Clear Differentiation

Internal structures of rickettsiae seen with phase contrast microscopy and in the electron microscope contain desoxyribonucleic acid and are therefore nuclear structures similar to those found in bacteria. They are minute spherical bodies, either single as in spherical rickettsiae or varying in number from 2 to 4 in rod-shaped forms. Occasional dumbbell-shaped chromatinic bodies are thought to represent these structures in the process of division. The presence of ribonucleic acid in the cytoplasm of rickettsiae was demonstrated with the use of ribonuclease and basic dyes. Rickettsiae therefore have a cellular organization similar to that of certain bacteria, with a clear differentiation into nuclear structure and cytoplasm.

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Fine structure of the walls of the conidia of various fungi and of the conidiophore of Fomes annosus

Australian Journal of Botany ◽

10.1071/bt9690013 ◽

1969 ◽

Vol 17 (1) ◽

pp. 13 ◽

Cited By ~ 5

Author(s):

G Scurfield ◽

Costa EWB Da

Keyword(s):

Fine Structure ◽

Phase Contrast ◽

Phase Contrast Microscopy ◽

Type Ii ◽

Surface Electron ◽

Opposite Pole ◽

Conidium Formation ◽

Contrast Microscopy ◽

Before And After ◽

Circular Arrangement

Light and phase contrast microscopy were used to investigate the structure and mode of formation of the conidia of various fungi. Conidial walls were examined with the electron microscope before and after chemical treatment of the walls to remove surface electron-opaque material. Two sorts of microfibrillar arrangement occurred: (i) a circular arrangement about an electron-opaque papilla at one pole which gives way to a more disperse arrangement at the opposite pole (Fomes annosus); (ii) a disperse arrangement (Pithomyces chartarum, Hormodendron resinae, Aschochyta pisi, Colleto- trichum lindemuthianurn). Conidial wall texture did not appear to be related to conidial ontogeny. Type (ii) conidia had perforate end walls. The occurrence of such walls is discussed in relation to spore formation and germination. The possibility that conidium formation involves the sequence: arrestment of growth →altered chemical composition and/or microfibrillar wall texture → swelling → conidium formation - is discussed on the basis of the microfibril arrangements in the conidiophore of Fomes annosus.

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Reversible inhibition of chondrogenic expression by certain hyaluronidase preparations

Development ◽

10.1242/dev.53.1.91 ◽

1979 ◽

Vol 53 (1) ◽

pp. 91-102

Author(s):

John P. Pennypacker ◽

Paul F. Goetinck

Keyword(s):

Growth Rate ◽

Phase Contrast ◽

The Other ◽

Phase Contrast Microscopy ◽

Embryonic Chick ◽

Minimum Concentration ◽

Contrast Microscopy ◽

Matrix Accumulation ◽

Testicular Hyaluronidase

Embryonic chick chondrocytes were cultured in the presence or absence of different preparations of testicular hyaluronidase. This treatment inhibited the accumulation of cartilage matrix as indicated by phase-contrast microscopy, by Alcian green staining, and by accumulation of 35S-labeled material. In addition, most preparations of testicular hyaluronidase caused a conversion of the cells to a fibroblastic phenotype characterized by a faster growth rate and the synthesis of type-1 collagen. This effect was found to beconcentrationdependent and was not observed at the minimum concentration of hyaluronidase required toinhibit matrix accumulation. Since two more highly purified hyaluronidase preparations prevented matrix accumulation but did not cause the fibroblastic transformation, it is likely that the conversion to a fibroblastic phenotype is caused by a contaminant in the other hyaluronidase preparations.

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