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.

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.

The relation between connective tissue cells and intercellular substances, including basement membranes

1975 ◽  
Vol 271 (912) ◽  
pp. 363-377 ◽  
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Immune Complexes ◽  
Hydrolytic Enzymes ◽  
Inflammatory Cells ◽  
Cell Types ◽  
Cellular Level ◽  
Basement Membranes ◽  
The Body ◽  
Pathological Changes

Basement membranes are distributed widely in the body forming an extracellular matrix for epithelial and endothelial cells. The collagenous and glycoprotein constituents of basement membranes are synthesized by these two cell types. Disturbance of the interactions between basement membranes and their associated epithelial and endothelial cells can lead to the pathological changes seen in diseases involving basement membranes. These changes are illustrated here by reference to glomerulonephritis induced by the deposition of immune complexes in the glomerulus of the kidney, and chronic inflammatory changes occurring in the lung after inhalation of asbestos. In these diseases basement membrane changes can occur in several ways. Hydrolytic enzymes released from inflammatory cells degrade basement membranes while other factors released from these cells may stimulate synthesis of basement membrane constituents by epithelial and endothelial cells. Alternatively the physical separation of epithelial and endothelial cells from their basement membranes by space-occupying substances such as immune complexes can interfere with feedback mechanisms leading to synthesis of basement membrane constituents and cell proliferation. Studies of these pathological changes at a cellular level should shed new light on the ways in which cells interact with their pericellular environment.

Mechanical Properties of the Porcine Lens Capsule

2008 ◽  
Author(s):  
Rouzbeh Amini ◽  
Alina Oltean ◽  
Vincent Barnett ◽  
Yoav Segal ◽  
Victor H. Barocas
Keyword(s):  
Mechanical Properties ◽  
Basement Membrane ◽  
Large Scale ◽  
Genetic Disorders ◽  
Genetic Mutation ◽  
Mechanical Tests ◽  
Lens Capsule ◽  
Basement Membranes ◽  
The Body ◽  
Ocular Abnormalities

Basement membranes are ubiquitous. In humans, genetic disorders in basement membranes can lead to many complications including kidney disease, skeletal muscle myopathy, hearing loss, and ocular abnormalities[1]. We hypothesize that genetic mutation of the microstructure of the lens capsule basement membrane will alter its mechanical properties. Because of its unique thickness and anatomically distinct margins, the lens capsule is the only site in the body where large-scale mechanical tests on the basement membrane can be made.

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.

The molecular basis of glomerular basement membrane disorders

2018 ◽  
Author(s):  
Rachel Lennon ◽  
Neil Turner
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Heparan Sulphate ◽  
Collagen Iv ◽  
Basement Membranes ◽  
Glomerular Disease ◽  
The Body ◽  
Monogenic Disorders ◽  
Filtration Barrier

The glomerular basement membrane (GBM) is a condensed network of extracellular matrix molecules which provides a scaffold and niche to support the function of the overlying glomerular cells. Within the glomerulus, the GBM separates the fenestrated endothelial cells, which line capillary walls from the epithelial cells or podocytes, which cover the outer aspect of the capillaries. In common with basement membranes throughout the body, the GBM contains core components including collagen IV, laminins, nidogens, and heparan sulphate proteoglycans. However, specific isoforms of these proteins are required to maintain the integrity of the glomerular filtration barrier.Across the spectrum of glomerular disease there is alteration in glomerular extracellular matrix (ECM) and a number of histological patterns are recognized. The GBM can be thickened, expanded, split, and irregular; the mesangial matrix may be expanded and glomerulosclerosis represents a widespread accumulation of ECM proteins associated with loss of glomerular function. Whilst histological patterns may follow a sequence or provide diagnostic clues, there remains limited understanding about the mechanisms of ECM regulation and how this tight control is lost in glomerular disease. Monogenic disorders of the GBM including Alport and Pierson syndromes have highlighted the importance of both collagen IV and laminin isoforms and these observations provide important insights into mechanisms of glomerular disease.

scholarly journals THE ANATOMIC SITE OF THE TRANSEPITHELIAL PERMEABILITY BARRIERS OF TOAD BLADDER

1969 ◽  
Vol 40 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Donald R. DiBona ◽  
Mortimer M. Civan ◽  
Alexander Leaf
Keyword(s):  
Basement Membrane ◽  
Plasma Membranes ◽  
Cell Layer ◽  
Single Layer ◽  
Cell Types ◽  
Physiological Data ◽  
Basal Cells ◽  
Granular Cells ◽  
Anatomic Site ◽  
Mucosal Epithelium

An examination of the mucosal epithelium of the urinary bladder of the toad reveals that the two major cell types which abut on the urinary surface, the granular and mitochondria-rich cells, also contact the basement membrane. Thus, the epithelium functions as a single cell layer. Although basal cells are interpolated between the granular cells and the basement membrane over a large portion of the epithelium, they do not constitute an additional continuous cell layer. This finding is consistent with extensive physiological data which had assumed that the major permeability barriers of this epithelium were the apical and basal-lateral plasma membranes of a single layer of cells.

scholarly journals Glomerulopathy in rats with streptozotocin diabetes. Accumulation of glomerular basement membrane analogous to human diabetic nephropathy.

1979 ◽  
Vol 149 (3) ◽  
pp. 623-631 ◽  
Author(s):  
M P Cohen ◽  
C V Klein
Keyword(s):  
Diabetic Nephropathy ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Renal Cortex ◽  
Streptozotocin Diabetes ◽  
Diabetic Rats ◽  
Basement Membranes ◽  
The Body ◽  
Diabetic Rat ◽  
Calculated Amount

Glomeruli from streptozotocin-diabetic and age-matched nondiabetic rats were quantitatively isolated by a differential sieving technique. The insoluble glomerular basement membranes were purified following sonic disruption in the presence of proteolytic inhibitors. The yield of glomeruli and of glomerular basement membrane relative to the amount of renal cortex and the body weight of the animals, as well as the calculated amount of basement membrane per glomerulus, were all significantly greater in diabetic rats when compared to non-diabetic controls. Glomerular basement membranes from normal and diabetic rats were solubilized by reduction and denaturation in the presence of SDS and subjected to agarose gel analysis. About 65% of both normal and diabetic basement membrane was solubilized by this procedure, and the elution profiles of non-diabetic and diabetic preparations were similar. These results suggest that rat renal basement membrane is qualitatively similar but quantitatively increased in streptozotocin-diabetes. Since glomerular enlargement and accumulation of basement membrane are characteristic of human diabetic nephropathy, the findings also suggest that the streptozotocin-diabetic rat is an appropriate animal model for studies relating to the pathogenesis of this complication of diabetes.

Systematic evaluation of microangiopathy in diabetic Chinese hamsters: I. Morphometric analysis of minimal glomerular basement membrane thickness in 19-23 month old Chinese hamsters

1984 ◽  
Vol 42 ◽  
pp. 190-191
Author(s):  
A.R. Diani ◽  
G.A. Sawada ◽  
T. Peterson ◽  
B.M. Wyse ◽  
M.C. Blanks ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Basement Membranes ◽  
The Body ◽  
Human Experimentation ◽  
Diabetic Microangiopathy ◽  
Diabetic Patients ◽  
Membrane Thickness ◽  
Metabolic Derangement ◽  
Basement Membrane Thickness ◽  
Chinese Hamsters

Microangiopathy has been recognized as a critical complication which afflicts the human diabetic population and magnifies the risk for permanent injury and/or mortality. One of the major manifestations of diabetic microvascular disease in man appears to be capillary basement membrane thickening (CBMT) which has been termed the “hallmark of diabetic microangiopathy”. CBMT of diabetic patients seems to be a product of vascular injury imposed by the interaction of metabolic derangement, environmental factors and genetics (1). Although the degree of thickening varies with age, duration of diabetes, severity of metabolic impairment and location in the body, capillary basement membranes from the kidney, skeletal muscle and heart are usually expanded in diabetic man. However, due to the sparsity of systematic studies and inherent problems with human experimentation, the pathogenesis of CBMT remains controversial. In an attempt to achieve a better understanding of the etiology and progression of CBMT, diabetic animal models have recently been the focal point of intensive research (2).

The nervous system and ciliary band of Müller’s larva

1982 ◽  
Vol 217 (1206) ◽  
pp. 37-58 ◽  
Keyword(s):  
Nervous System ◽  
Basement Membrane ◽  
The Body ◽  
Sensory Cells ◽  
Ciliary Band ◽  
Electron Microscopical Level ◽  
The Central Nervous System ◽  
Electron Microscopical ◽  
Pass Through ◽  
The Right

The newly hatched Müller’s larva of the polyclad Pseudoceros canadensis is described at the electron microscopical level with attention to the arrangement and innervation of the ciliary band and the organization of the larval nervous system. Distinctive ultrastructural features allow the trochal cells of the band to be distinguished from general epithelium of the body surface and the specialized oral field epithelium. The band comprises a ventral and a dorsal marginal loop that run along the margins of the six projecting lobes of the larva, and a suboral plate that forms a bridge between these behind the mouth. These three components are joined asymmetrically to form a single, but discontinuous, band: on the left the ventral loop and suboral plate are joined, but these fail to connect with the dorsal loop; on the right it is the ventral and dorsal loops that join, but there is no connection between these and the suboral plate. A system of intraepithelial nerves is associated with the ciliary band, the largest nerves being those in the ventrolateral lobes and the intraepithelial commissure that connects these across the oral field. The system is truly peripheral: it lies outside the basement membrane and is separated by it from the central nervous system, which at this stage comprises a brain and four radiating nerve cords. The peripheral and central nervous systems are in direct contact only at two points, located just behind the ventrolateral lobes on either side of the larva, where a few neurites pass through the basement membrane from one system to the other. The neurites of the peripheral system arise mainly from bipolar sensory cells located in the ciliary band. These are concentrated along the ventrolateral lobes, and their projecting cilia face incoming water currents. Observations on larval swimming behaviour do not, however, suggest any obvious function for these cells. The ciliary band is thus organized as a self-contained unit supplying its own innervation. Other primitive invertebrate larvae have ciliary bands that are similar to some extent in their organization and ultra­structure. This, added to what is already known about Müller’s larva, supports the idea that it is primitive and is closely related to at least several other larval types, but it is not clear how the overall arrangement of the band in Müller’s larva as described here relates to what is seen in other larvae. Several ways in which the pattern might have originated from simpler patterns in hypothetical ancestral forms are, however, discussed.

An Electron Microscopical Study of the Innervation and Sarcoplasmic Reticulum of the Fibrillar Flight Muscle of Drosophila Melanogaster

1964 ◽  
Vol s3-105 (69) ◽  
pp. 1-6 ◽  
Author(s):  
S. AHMAD SHAFIQ
Keyword(s):  
Drosophila Melanogaster ◽  
Plasma Membrane ◽  
Sarcoplasmic Reticulum ◽  
Peripheral Nerves ◽  
Plasma Membranes ◽  
Flight Muscle ◽  
Microscopical Study ◽  
Electron Microscopical Study ◽  
Electron Microscopical

The peripheral nerves of Drosophila are of the ‘tunicated’ type; their mesaxons are derived from several independent invaginations of the lemnoblast plasma membrane and possess septate desmosomes. Fine branches of the nerves and tracheoles penetrate deeply into the fibres of the flight muscle and draw the sarcolemma in with them. The myoneural junctions occur on the invaginated portions of the sarcolemma. The axons shed their lemnoblastic elements and become closely apposed to the muscle plasma membranes at the junctions. The sarcoplasmic reticulum of the flight muscle seems to consist mainly of the extensive infoldings of the sarcolemma and their processes, as in Tenebrio. ‘Dyads’ formed by the association of isolated vesicles with the membranous infoldings are present in Drosophila. Most of these ‘dyads’ seem to be in register with the myofibrils, two pairs being associated with each sarcomere.

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