An Enzyme Histochemical and Electron Microscopical Study of the Light Organ of the Glow-worm, Lampyris noctiluca

1965 ◽  
Vol s3-106 (75) ◽  
pp. 247-260
Author(s):  
V. C. BARBER ◽  
C.W. T. PILCHER
Keyword(s):  
Electron Microscopy ◽  
Calcium Ions ◽  
Adenosine Triphosphatase ◽  
Microscopical Study ◽  
The Body ◽  
Light Organ ◽  
Light Organs ◽  
Histochemical Tests ◽  
Electron Microscopical ◽  
Alkaline And Acid Phosphatase

The light organs of female specimens of the glow-worm Lampyris noctiluca were investigated by enzyme histochemical tests, lipid stains, and electron microscopy. Differences, both histochemical and in fine structure, were found between the cells of the photocyte and reflector layers. The photocytes contained a vesiculated reticulum, photocyte granules, amorphous granules, and numerous mitochondria. The reflecter layer did not contain the reticulum or the two types of granules and there were fewer mitochondria. Glycogen granules, and spaces possibly caused by the removal of urate during preparatory procedures, were present in this layer but absent from the photocytes. All the dehydrogenase enzymes, except for glucose-6-phosphate, 6 phosphogluconic, lactic, and β-hydroxybutyric dehydrogenases, which were absent from both layers, showed more activity in the photocyte layer, NADH2 and NADPH2 diaphorase showed no activity in the reflector layer. A transition zone between the two layers was demonstrated both histochemically and morphologically. Alkaline and acid phosphatase could not be demonstrated in the light organ. The adenosine triphosphatase demonstrable in the organ was not activated by magnesium but was activated by calcium ions. Lipid was present in both layers of the organ. The tracheolar supply to the photocytes was good but no tracheolar end organs were observed. The dehydrogenase activity of the body musculature is also reported upon.

Light Organ and Eyestalk Compensation to Body Tilt in the Luminescent Midwater Shrimp, Sergestes Similis

1982 ◽  
Vol 98 (1) ◽  
pp. 83-104
Author(s):  
MICHAEL I. LATZ ◽  
JAMES F. CASE
Keyword(s):  
Angular Distribution ◽  
Light Source ◽  
The Body ◽  
Body Tilt ◽  
Light Organ ◽  
Total Compensation ◽  
Angular Movement ◽  
Counter Rotation ◽  
Light Organs ◽  
Before And After

The posterior light organ and eyestalk of the midwater shrimp, Sergestes similis Hansen, are capable of 140° of angular movement within the body during pitch body tilt, maintaining the organs at near horizontal orientations. Counter-rotations compensate for 74–80% of body inclination. These responses are statocyst mediated. Unilateral statolith ablation reduces compensation by 50%. There is no evidence for either homolateral or contralateral control by the single functioning statocyst. Bilateral lith ablation abolishes counter-rotation. Light organ and eyestalk orientations are unaffected by the direction of imposed body tilt. Bioluminescence is emitted downward from horizontal animals with an angular distribution similar to the distribution of oceanic light. The amount of downward directed luminescence in tilted animals decreases at large angles of body inclination due to less than total compensation by the light organs. Eye turning towards a light source is induced by upward-directed illumination. The resulting change in eyestalk orientations never amounts to more than 25°. The turning is abolished by bilateral statolith ablation. Downward directed illumination, comparable in intensity to oceanic light, generally does not generate significant eye turning. Light organ orientations remain unaffected by directional illumination, both before and after bilateral statolith ablation. The compensatory counter-rotations by the posterior light organ and eyestalk suggest that counter-illumination by S. similis remains effective in inclined animals.

Further observations on green flagellates with scaly flagella: the genus Heteromastix korshikov

1965 ◽  
Vol 45 (1) ◽  
pp. 241-255 ◽  
Author(s):  
I. Manton ◽  
D. G. Rayns ◽  
H. Ettl ◽  
M. Parke
Keyword(s):  
Marine Species ◽  
Microscopical Study ◽  
The Body ◽  
Fibrous Root ◽  
Colour Reaction ◽  
New Findings ◽  
Normal Colour ◽  
Important Addition ◽  
Electron Microscopical ◽  
Genus One

A light and electron microscopical study has been carried out on the morphology and microanatomy of two marine species of Heteromastix and less completely on two freshwater samples from the same genus, one only of which is named; this one is, however, important as the type species of the genus (H. angulata Korsh.). Agreement in salient features indicates that Bipedinomonas N. Carter andAnisomonas Butcher, under which the marine species were previously described, should be discarded as later synonyms of Heteromastix Korsh. Apart from the nomenclatural clarification the most important new findings concern the details of the periplast on cell body and flagella, the presence of stellate scales as well as plate-scales on both types of surface, the presence within the body of a starch shell not giving the normal colour reaction with iodine, and of a characteristic fibrous ‘root’ joining the flagellar bases to the plastid surface. A major finding of electron microscopical interest is the clarity with which the formation of scales and of flagellar hairs has been traced to the Golgi cisternae. These observations are an important addition to previous knowledge concerning genera of related green flagellates possibly referable to the class Prasinophyceae.

scholarly journals ELECTRON MICROSCOPICAL STUDY OF SKELETAL MUSCLE DURING ISOTONIC (AFTERLOAD) AND ISOMETRIC CONTRACTION

1956 ◽  
Vol 2 (2) ◽  
pp. 201-211 ◽  
Author(s):  
G. G. Knappeis ◽  
F. Carlsen
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Isometric Contraction ◽  
Sarcomere Length ◽  
Microscopical Study ◽  
Electron Microscopical Study ◽  
Semitendinosus Muscle ◽  
Electron Microscopical ◽  
Contraction Band

Bundles of the curarized semitendinosus muscle of the frog were fixed during isotonic (afterload) and isometric contraction and the length of the A and I bands investigated by electron microscopy. The sarcomere length, during afterload contraction initiated at 25 per cent stretch, varied depending on the afterload applied between 3.0 and 1.2 µ, i.e. the shortening amounted to 5 to 50 per cent. The shortening involved both the A and I bands. Between a sarcomere length of 3.0 to 1.7 µ (shortening 5 to 35 per cent) the A bands remained practically constant at about 1.5 µ (6 to 8 per cent shortening); the length of the I bands decreased from 1.4 to 0.3 µ (80 per cent shortening). Below a sarcomere length of 1.7 to 1.2 µ the A bands shortened from 1.5 to 1.0 µ (from 6 to 8 to 25 per cent). At sarcomere lengths 1.6 to 1.2 µ the I band was replaced by a contraction band. During isometric contraction the A bands shortened by about 8 to 10 per cent; the I bands were correspondingly elongated.

The differentiation of mouse gonads in vitro: a light and electron microscopical study

Development ◽  
1986 ◽  
Vol 97 (1) ◽  
pp. 189-199
Author(s):  
Sarah Mackay ◽  
Robert A. Smith
Keyword(s):  
Electron Microscopy ◽  
Culture Medium ◽  
Light And Electron Microscopy ◽  
Calf Serum ◽  
Microscopical Study ◽  
Electron Microscopical Study ◽  
The Other ◽  
Foetal Calf Serum ◽  
Electron Microscopical

Indifferent urogenital complexes were excised from mouse foetuses assessed by developmental criteria as day 10·5 or 11. After 4 or 6–7 days in culture, complexes were fixed and examined by light and electron microscopy. The effect of culturing sexed complexes in mixed sex groups was investigated. The effect of the presence or absence of foetal calf serum in the culture medium was considered. No evidence of inhibition of one sex by the other was found. Ovaries developed further in cultures than testes.

Electron Microscope and Histochemical Observations on the Daughter Sporocyst of Schistosoma mattheei and Schistosoma bovis

1971 ◽  
Vol 45 (2-3) ◽  
pp. 237-244 ◽  
Author(s):  
G. K. Kinoti ◽  
R. G. Bird ◽  
Mary Barker
Keyword(s):  
Electron Microscopy ◽  
Alkaline Phosphatase ◽  
Body Wall ◽  
The Body ◽  
Active Process ◽  
Collagen Fibres ◽  
Daughter Sporocyst ◽  
Schistosoma Bovis ◽  
Electron Microscopical ◽  
Snail Tissue

Electron-microscopical, histological and histochemical observations were carried out on the body wall of the daughter sporocyst stage of Schistosoma mattheei and S. bovis. Electron microscopy revealed that the body wall consists of a continuous outer layer of cytoplasm, collagen fibres, fibroblasts and a layer of somatic cells which are apparently continuous with the cytoplasmic layer. This layer forms numerous microvilli at the surface.Pronounced alkaline phosphatase activity was found in the sporocyst body wall, but no evidence of esterases was found in the parasite although esterase activity was readily demonstrated in the snail tissue that the schistosome parasitized.It is concluded that the passage of substances such as glucose across the surface of the sporocyst is an active process probably mediated by enzymes and that little, if any, lipid metabolism occurs in the sporocyst stage.

The Effect of Certain Fixatives on Particles of a Globular Protein: An Electron-Microscopical Study

1964 ◽  
Vol s3-105 (70) ◽  
pp. 227-230
Author(s):  
K. DEUTSCH ◽  
E. FISCHER ◽  
W. KRAUSE
Keyword(s):  
Electron Microscopy ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Potassium Permanganate ◽  
Bovine Serum ◽  
Osmium Tetroxide ◽  
Microscopical Study ◽  
Globular Protein ◽  
Electron Microscopical Study ◽  
Electron Microscopical

Particles (regarded as molecules) of bovine serum albumin have been studied by electron microscopy both in the untreated state and after fixation with osmium tetroxide, formaldehyde, and potassium permanganate. All three fixatives, especially potassium permanganate, increased the density of the particles considerably.

Further studies on the rectal complex of mealworm tenebrio molitor , L. (Coleoptera, Tenebrioidae)

1968 ◽  
Vol 253 (788) ◽  
pp. 343-382 ◽  
Keyword(s):  
Basement Membrane ◽  
Plasma Membranes ◽  
External Medium ◽  
Single Layer ◽  
Microscopical Study ◽  
Basement Membranes ◽  
The Body ◽  
Outer Sheath ◽  
Tubule Cells ◽  
Electron Microscopical

An electron microscopical study has been made of the rectal complex. The perinephric membrane is a complicated structure which, in the posterior region, comprises an inner and an outer sheath separated by a space containing tracheolar end cells. The outer sheath is formed of a single layer of cells covered by an external basement membrane. The inner sheath is a multi-laminate structure made up of many thin, cellular layers which in places are reduced to closely apposed plasma membranes. Anteriorly the cellular layers are reduced in number, but each layer is of greater thickness; they finally terminate where the perinephric membrane is applied to the intestine. Posteriorly the inner sheath makes contact with the rectal epithelium. An earlier description identified three spaces within the rectal complex: the perirectal, subepithelial and peritubular spaces. The first two are true intercellular spaces, bounded by basement membranes, but the so-called peritubular space is occupied by necrotic cells. The inner sheath of the perinephric membrane is interrupted by the leptophragmata. Each leptophragma is bounded by a prominent electron-dense ring into which the laminae of the inner sheath are inserted. The outer sheath forms a blister over the leptophragma and is completely noncellular in this region. At the base of the blister a basement membrane covers the leptophragma itself, and the body of the leptophragma cell projects into the lumen of the tubule, with a thin layer of cytoplasm lying beneath the basement membrane. Both this layer and the cell body itself bear microvilli. The cell has a normal complement of mitochondria, but these do not invade the microvilli. In this last respect the ordinary tubule cells differ from the leptophragma cells in that most of their microvilli contain mitochondria, with connexions between the outer mitochondrial m em brane and the plasma membrane. The tubule cells have a poorly developed endoplasmic reticulum but are filled with numerous small granules; basal infoldings are restricted to those parts of the cell which face the perirectal space. The permeability of the perinephric membrane has been re-investigated and it is shown that the m em brane is more permeable to water and solutes at the anterior end, as might be expected if the inner sheath were the main barrier. Using preparations isolated in small volumes of haemolymph or other external media it has been shown that the rectal complex takes up potassium against a gradient of concentration. The lumen of the perirectal tubule is some 50 m V positive with respect to the external medium, so the uptake of potassium must be active. The leptophragma is freely permeable to chloride and this ion appears to enter the tubule passively. A model of the mechanism of the rectal complex is proposed, whose main feature is that the high osmolarity of the fluids within the rectal complex is brought about by the inward secretion of potassium chloride, unaccompanied by water, at the leptophragmata. This should result in a fall in the osmolarity of the external medium. A substantial fall has been observed on occasion, but in most experiments a fall is barely detectable. It is believed that the impermeability of the leptophragmata to water is rapidly lost in a deteriorating preparation.

A light optical diffractometer for electron microscopical images operating in line

1978 ◽  
Vol 36 (1) ◽  
pp. 86-87
Author(s):  
P. Bonhomme ◽  
A. Beorchia
Keyword(s):  
Electron Microscopy ◽  
Electron Transfer ◽  
Electron Microscope ◽  
Image Converter ◽  
Coherent Light ◽  
Spatial Filters ◽  
Electron Image ◽  
Electron Microscopical ◽  
Working Parameters ◽  
Amorphous Part

We have already described (1.2.3) a device using a pockel's effect light valve as a microscopical electron image converter. This converter can be read out with incoherent or coherent light. In the last case we can set in line with the converter an optical diffractometer. Now, electron microscopy developments have pointed out different advantages of diffractometry. Indeed diffractogram of an image of a thin amorphous part of a specimen gives information about electron transfer function and a single look at a diffractogram informs on focus, drift, residual astigmatism, and after standardizing, on periods resolved (4.5.6). These informations are obvious from diffractogram but are usualy obtained from a micrograph, so that a correction of electron microscope parameters cannot be realized before recording the micrograph. Diffractometer allows also processing of images by setting spatial filters in diffractogram plane (7) or by reconstruction of Fraunhofer image (8). Using Electrotitus read out with coherent light and fitted to a diffractometer; all these possibilities may be realized in pseudoreal time, so that working parameters may be optimally adjusted before recording a micrograph or before processing an image.

Ultrastructure of the soil fungus, Geomyces pannorus

1984 ◽  
Vol 42 ◽  
pp. 738-739
Author(s):  
J. A. Traquair ◽  
E. G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fine Structure ◽  
Low Temperatures ◽  
Soil Fungus ◽  
Organic Soils ◽  
Anatomical Studies ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Scanning Electron

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.

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