Metamorphosis of the perirectal Malpighian tubules in the mealworm Tenebrio molitor L. (Coleoptera, Tenebrionidae). I. Histology and histochemistry

1971 ◽  
Vol 49 (6) ◽  
pp. 823-830 ◽  
Author(s):  
J. R. Byers
Keyword(s):  
Adult Development ◽  
Brush Border ◽  
Fluid Transport ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Cellular Level ◽  
Malpighian Tubules ◽  
Large Numbers ◽  
Tubule Cells ◽  
Coleoptera Tenebrionidae

The perirectal Malpighian tubules of both larva and adult T. molitor are highly specialized for a fluid transport role. Related to this function are a number of structural specializations, including a thick brush border which lines the lumen of the tubules. The brush border consists of closely packed microvilli containing mitochondria. Although the perirectal tubules survive the transformation from larva to adult they undergo at the cellular level a sequence of dramatic changes. During the early stages of metamorphosis there is a phase of dedifferentiation and autolysis involving the partial breakdown of the brush border and the destruction of large numbers of mitochondria. A conspicuous cytological manifestation of these processes is the transfer of membrane lipids from the brush border into intracellular osmiophilic bodies (autolysosomes). During the later stages of metamorphosis, i.e. adult development, the cells progressively redifferentiate. As the brush border is rebuilt there is an increase in the number of mitochondria concomitant with a decline in the number of osmiophilic bodies, indicating that the membrane lipid is reutilized for mitochondrial genesis.The results show that the processes of isolation and digestion of mitochondria, the accumulation and retention of valuable breakdown products, and their subsequent reutilization are integral parts of the economy of the perirectal tubule cells during metamorphosis.

Metamorphosis of the perirectal Malpighian tubules in the mealworm Tenebrio molitor L. (Coleoptera, Tenebrionidae). II. Ultrastructure and role of autophagic vacuoles

1971 ◽  
Vol 49 (8) ◽  
pp. 1185-1191 ◽  
Author(s):  
J. R. Byers
Keyword(s):  
Brush Border ◽  
Fluid Transport ◽  
Membrane Lipid ◽  
Structure And Function ◽  
Malpighian Tubules ◽  
Autophagic Vacuoles ◽  
Tubule Cells ◽  
And Function ◽  
Coleoptera Tenebrionidae

The perirectal Malpighian tubules of T. molitor are highly specialized for ion and fluid transport. Although they survive metamorphosis, being similar in structure and function in both larva and adult, they undergo a sequence of dramatic alterations in subcellular organization. In the early stages of metamorphosis there is a phase of dedifferentiation during which the perirectal tubule cells undergo degenerative changes. The highly specialized brush border, which in the larva is formed of closely packed microvilli containing mitochondria, is partially broken down and a large number of mitochondria undergo autophagic isolation and digestion. A conspicuous result of the autophagic processes is the accumulation of membrane lipid within autophagic vacuoles which are eventually transformed into 'osmiophilic bodies.' During the later stages of metamorphosis the cells progressively redifferentiate and the brush border is reconstituted. The number of osmiophilic bodies declines markedly, concomitant with an apparent increase in the number of mitochondria.

Ischemia-induced loss of epithelial polarity: potential role of the actin cytoskeleton

1991 ◽  
Vol 260 (6) ◽  
pp. F769-F778 ◽  
Author(s):  
B. A. Molitoris
Keyword(s):  
Proximal Tubule ◽  
Membrane Lipids ◽  
Basolateral Membrane ◽  
Surface Membrane ◽  
Membrane Lipid ◽  
Epithelial Polarity ◽  
Membrane Domains ◽  
Cortical Actin ◽  
Proximal Tubule Cells ◽  
Tubule Cells

Proximal tubule cells play a major role in the reabsorption of ions, water, and solutes from the glomerular filtrate. This is accomplished, in large part, by a surface membrane polarized into structurally, biochemically, and physiologically distinct apical and basolateral membrane domains separated by cellular junctional complexes. Establishment and maintenance of these unique membrane domains is essential for the normal functioning of proximal tubular cells and is dependent on cortical actin cytoskeletal-surface membrane interactions. Ischemia results in the duration-dependent loss of apical and basolateral surface membrane lipid and protein polarity. This loss of surface membrane polarity is associated with disruption of the cortical actin microfilament network and the opening of cellular tight junctions. Surface membrane lipids and proteins are then free to diffuse laterally within the membrane bilayer into the alternate membrane domain. Functionally, ischemia-induced loss of epithelial polarity is, in part, responsible for reduced sodium and glucose reabsorption. With recovery, proximal tubule cells undergo remodeling of the surface membrane such that the unique apical and basolateral membrane domains are reestablished allowing normal cellular function to return.

scholarly journals New insights into the cell biology of ischemic acute renal failure.

1991 ◽  
Vol 1 (12) ◽  
pp. 1263-1270 ◽  
Author(s):  
B A Molitoris
Keyword(s):  
Proximal Tubule ◽  
Cell Biology ◽  
Membrane Lipids ◽  
Basolateral Membrane ◽  
Surface Membrane ◽  
Membrane Lipid ◽  
Membrane Domains ◽  
Proximal Tubule Cells ◽  
Glomerular Filtrate ◽  
Tubule Cells

Proximal tubule cells play an essential role in the reabsorption of ions, water, and solutes from the glomerular filtrate. This is accomplished, in large part, by having a surface membrane polarized into structurally, biochemically, and physiologically distinct apical and basolateral membrane domains separated by cellular junctional complexes. Establishment and maintenance of these unique membrane domains are essential for the normal functioning of the cell. Ischemia results in the duration-dependent loss of apical and basolateral surface membrane lipid and protein polarity. Loss of surface membrane polarity is preceded by disruption of the microfilament network and opening of cellular tight junctions. Surface membrane lipids and proteins are then free to diffuse laterally within the bilayer into the alternate membrane domain. Functionally, ischemia-induced loss of epithelial polarity has been shown to be responsible for reduced sodium and glucose reabsorption. Reduced Na+ reabsorption has been related to redistribution of Na+, K(+)-ATPase into the apical membrane. During recovery from ischemic injury, proximal tubule cells undergo remodeling of the surface membrane such that the unique apical and basolateral membrane domains are reestablished, allowing for the return of normal cellular function.

Stimulation of sodium transport and fluid secretion by ouabain in an insect malpighian tubule

1988 ◽  
Vol 137 (1) ◽  
pp. 265-276 ◽  
Author(s):  
S. H. Maddrell ◽  
J. A. Overton
Keyword(s):  
Fluid Flow ◽  
Sodium Transport ◽  
Fluid Transport ◽  
Electrical Potential ◽  
Malpighian Tubule ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
Sodium Ions ◽  
Tubule Cells ◽  
Stimulation Of

Ouabain, at all concentrations higher than 2 × 10(−7) mol l-1, stimulates the rate at which the Malpighian tubules of the insect, Rhodnius, transport sodium ions and fluid into the lumen. An effect on paracellular movement of sodium ions is unlikely because ouabain makes the electrical potential of the lumen more positive, which would slow diffusion of sodium into the lumen. Radioactive ouabain binds to the haemolymph-facing sides of the tubule cells but not to the luminal face. This binding is reduced in the presence of elevated levels of potassium or of non-radioactive ouabain. Bound ouabain is only slowly released on washing in ouabain-free saline. The evidence suggests that there is a Na+/K+-ATPase on the outer (serosal) membranes of the tubules. Such a pump would transport sodium in a direction opposed to the flow of ions and water involved in fluid transport; poisoning it with ouabain would remove this brake, and fluid flow and sodium transport would increase, as observed.

scholarly journals Lipid Remodeling Confers Osmotic Stress Tolerance to Embryogenic Cells during Cryopreservation

2021 ◽  
Vol 22 (4) ◽  
pp. 2174
Author(s):  
Liang Lin ◽  
Junchao Ma ◽  
Qin Ai ◽  
Hugh W. Pritchard ◽  
Weiqi Li ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Technology Development ◽  
Membrane Lipids ◽  
Species Conservation ◽  
Membrane Lipid ◽  
Cell Integrity ◽  
Embryogenic Cells ◽  
Osmotic Stress Tolerance ◽  
Lipid Species ◽  
Magnolia Officinalis

Plant species conservation through cryopreservation using plant vitrification solutions (PVS) is based in empiricism and the mechanisms that confer cell integrity are not well understood. Using ESI-MS/MS analysis and quantification, we generated 12 comparative lipidomics datasets for membranes of embryogenic cells (ECs) of Magnolia officinalis during cryogenic treatments. Each step of the complex PVS-based cryoprotocol had a profoundly different impact on membrane lipid composition. Loading treatment (osmoprotection) remodeled the cell membrane by lipid turnover, between increased phosphatidic acid (PA) and phosphatidylglycerol (PG) and decreased phosphatidylcholine (PC) and phosphatidylethanolamine (PE). The PA increase likely serves as an intermediate for adjustments in lipid metabolism to desiccation stress. Following PVS treatment, lipid levels increased, including PC and PE, and this effectively counteracted the potential for massive loss of lipid species when cryopreservation was implemented in the absence of cryoprotection. The present detailed cryobiotechnology findings suggest that the remodeling of membrane lipids and attenuation of lipid degradation are critical for the successful use of PVS. As lipid metabolism and composition varies with species, these new insights provide a framework for technology development for the preservation of other species at increasing risk of extinction.

scholarly journals Impact of Membrane Lipids on UapA and AzgA Transporter Subcellular Localization and Activity in Aspergillus nidulans

2021 ◽  
Vol 7 (7) ◽  
pp. 514
Author(s):  
Mariangela Dionysopoulou ◽  
George Diallinas
Keyword(s):  
Plasma Membrane ◽  
Subcellular Localization ◽  
Aspergillus Nidulans ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Lipid Biosynthesis ◽  
Transport Kinetics ◽  
Negative Effect ◽  
And Function

Recent biochemical and biophysical evidence have established that membrane lipids, namely phospholipids, sphingolipids and sterols, are critical for the function of eukaryotic plasma membrane transporters. Here, we study the effect of selected membrane lipid biosynthesis mutations and of the ergosterol-related antifungal itraconazole on the subcellular localization, stability and transport kinetics of two well-studied purine transporters, UapA and AzgA, in Aspergillus nidulans. We show that genetic reduction in biosynthesis of ergosterol, sphingolipids or phosphoinositides arrest A. nidulans growth after germling formation, but solely blocks in early steps of ergosterol (Erg11) or sphingolipid (BasA) synthesis have a negative effect on plasma membrane (PM) localization and stability of transporters before growth arrest. Surprisingly, the fraction of UapA or AzgA that reaches the PM in lipid biosynthesis mutants is shown to conserve normal apparent transport kinetics. We further show that turnover of UapA, which is the transporter mostly sensitive to membrane lipid content modification, occurs during its trafficking and by enhanced endocytosis, and is partly dependent on autophagy and Hect-type HulARsp5 ubiquitination. Our results point out that the role of specific membrane lipids on transporter biogenesis and function in vivo is complex, combinatorial and transporter-dependent.

scholarly journals The fate and function of glycosphingolipid glucosylceramide

2003 ◽  
Vol 358 (1433) ◽  
pp. 869-873 ◽  
Author(s):  
Gerrit van Meer ◽  
Jasja Wolthoorn ◽  
Sophie Degroote
Keyword(s):  
Cellular Differentiation ◽  
Membrane Lipids ◽  
Early Stage ◽  
Cellular Level ◽  
Mature Stage ◽  
Storage Diseases ◽  
Head Groups ◽  
Biological Studies ◽  
Intracellular Membrane Transport ◽  
And Function

In higher eukaryotes, glucosylceramide is the simplest member and precursor of a fascinating class of membrane lipids, the glycosphingolipids. These lipids display an astounding variation in their carbohydrate head groups, suggesting that glycosphingolipids serve specialized functions in recognition processes. It is now realized that they are organized in signalling domains on the cell surface. They are of vital importance as, in their absence, embryonal development is inhibited at an early stage. Remarkably, individual cells can live without glycolipids, perhaps because their survival does not depend on glycosphingolipid–mediated signalling mechanisms. Still, these cells suffer from defects in intracellular membrane transport. Various membrane proteins do not reach their intracellular destination, and, indeed, some intracellular organelles do not properly differentiate to their mature stage. The fact that glycosphingolipids are required for cellular differentiation suggests that there are human diseases resulting from defects in glycosphingolipid synthesis. In addition, the same cellular differentiation processes may be affected by defects in the degradation of glycosphingolipids. At the cellular level, the pathology of glycosphingolipid storage diseases is not completely understood. Cell biological studies on the intracellular fate and function of glycosphingolipids may open new ways to understand and defeat not only lipid storage diseases, but perhaps other diseases that have not been connected to glycosphingolipids so far.

A Study of the Malpighian Tubules of the Pill Millipede, Glomeris marginata (Villers)

1974 ◽  
Vol 60 (1) ◽  
pp. 41-51
Author(s):  
PATRICIA ANNE FARQUHARSON
Keyword(s):  
Size Distribution ◽  
Fluid Transport ◽  
Molecular Size ◽  
Malpighian Tubules ◽  
Inverse Relation ◽  
Fluid Production ◽  
Molecular Size Distribution ◽  
Molecular Sieving ◽  
Tubule Fluid ◽  
Tubule Wall

1. Tubule fluid:medium ratios (TF/M) have been measured for inulin, glucose, LMWD and HMWD. These TF/M ratios were surprisingly high. 2. The tubule appears to act as a molecular filter; that is to say, molecules move through the tubule wall in inverse relation to their size. This is best illustrated using polyvinyl pyrrolidone as a tracer. The molecular size distribution of PVP fractions present in tubule fluid differs markedly from the molecular size distribution of PVP in the bathing Ringer. 3. No correlation can be made between the inulin and glucose TF/M and the rate of fluid production. However, the inverse relationship between TF/M and rate of fluid production for dextrans indicates a molecular sieving effect. 4. The significance of these results is discussed with reference to models of fluid transport.

THE EFFECTS OF MANDUCA SEXTA DIURETIC HORMONE ON FLUID TRANSPORT BY THE MALPIGHIAN TUBULES AND CRYPTONEPHRIC COMPLEX OF MANDUCA SEXTA

1993 ◽  
Vol 178 (1) ◽  
pp. 231-243 ◽  
Author(s):  
N. Audsley ◽  
G. M. Coast ◽  
D. A. Schooley
Keyword(s):  
Cyclic Amp ◽  
Manduca Sexta ◽  
Fluid Transport ◽  
Basal Membrane ◽  
Fluid Secretion ◽  
Hormonal Control ◽  
Malpighian Tubules ◽  
Proximal Tubules ◽  
Fluid Absorption ◽  
Diuretic Hormone

1. Manduca sexta diuretic hormone (Mas-DH) stimulates fluid secretion by adult Malpighian tubules of M. sexta, demonstrating its site of diuretic action in M. sexta for the first time. It was not possible to develop a suitable bioassay to measure fluid secretion in larval proximal tubules. 2. Mas-DH has an antidiuretic action on the cryptonephric complex of larval M. sexta because it increases fluid absorption from the rectum. It appears that in this complex Mas-DH is acting on a Na+/K+/2Cl- co-transporter, presumably on the basal membrane of the cryptonephric Malpighian tubules, because Mas-DH-stimulated fluid absorption by the cryptonephric complex is inhibited by bumetanide or the removal of Cl-, Na+ or K+ from the haemolymph side of the tissue. This is the first demonstration of hormonal control of fluid absorption by the cryptonephric complex. 3. Concomitant with the stimulation of fluid transport, Mas-DH increases the amount of cyclic AMP secreted by adult Malpighian tubules and the cryptonephric complex. In addition, Mas-DH promotes cyclic AMP production by the larval proximal tubules.

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