Multiple Functions of Malpighian Tubules in Insects: A Review (original) (raw)
Related papers
Comparative physiology of Malpighian tubules: form and function
Open Access Insect Physiology, 2016
Malpighian tubules (MTs) are the main osmoregulatory and excretory organs of insects and are considered analogous to the nephridia or kidneys, the corresponding organs of annelids and the vertebrates. MTs are responsible for the production of an isosmotic filtrate from hemolymph, the primary urine, which carries excretory products of metabolism and toxic compounds into the hindgut. The MTs of Drosophila (Diptera), the more representative studied insect, develop from the hindgut primordium and visceral mesoderm. Once formed, tubules in Diptera can grow in size to answer the increasing demands on osmotic and ionic regulation and renal clearance. However, there are up to 30 million species of insects occupying several ecological niches; therefore we can conclude that our models of transport and control of MTs cannot be generalistic. In this synthetic review, morphological and ultrastructural figures from hymenoptera, such as bees and ants, have been provided to illustrate the MTs from other insect groups. These organs have been widely used in ecotoxicological studies, as they quickly respond to changes in the insect's environment, and the tubules induce detoxification genes. The large number of scientific manuscripts around the world indicates that the MTs can be used for evaluation of biomarkers, detoxification, innate immunity, and as models for human renal diseases. Other studies have suggested that stem cells and progenitor cells may be involved in the repair and regeneration of injured renal tissue. Considering the different habitats of all organisms that have MTs, we can expect that the new techniques available for sequencing DNA and mRNA and the development of the omic-sciences, with the imminent sequencing of multiple insect genomes, will provide new data and further elucidate the different mechanisms by which MTs perform their functions.
Fluid Secretion by the Malpighian tubules of Insects
Philosophical Transactions of the Royal Society B: Biological Sciences, 1971
Malpighian tubules of insects typically secrete an iso-osmotic fluid by a process which is thought to involve the following: (1) Potassium ions enter the tubule cells by a process which is sodium dependent and which may be active; they are then actively pumped into the lumen by an electrogenic pump. (2) Sodium ions cross the wall in a similar fashion to potassium ions but their entry into the cells is very restricted so that they are transported only slowly. (3) These active cation movements create a trans-wall potential favouring the passive movements of anions from the haemolymph into the lumen. (4) With one exception, smaller anions appear to cross the wall faster than do larger ones. The exception is that phosphate ions cross faster than any other anion in spite of their large size. The evidence suggests that this is more likely to be achieved by facilitated diffusion but active movements are not excluded. (5) The apical and basal membranes of the tubule cells are elaborately fo...
Malpighian tubules (MpTs) are the major organ for excretion and osmoregulation in most insects. MpT development is characterised for Drosophila melanogaster, but not other species. We therefore do not know the extent to which the MpT developmental programme is conserved across insects. To redress this we provide a comprehensive description of MpT development in the beetle Tribolium castaneum (Coleoptera), a species separated from Drosophila by >315 million years. We identify similarities with Drosophila MpT development including: 1) the onset of morphological development, beginning when tubules bud from the gut and proliferate to increase organ size. 2) the tubule is shaped by convergent-extension movements and oriented cell divisions. 3) differentiated tip cells activate EGF-signalling in distal MpT cells through the ligand Spitz. 4) MpTs contain two main cell types – principal and stellate cells, differing in morphology and gene expression. We also describe development of the beetle cryptonephridial system, an adaptation for water conservation, which represents a major modification of the MpT ground plan characterised by intimate association between MpTs and rectum. This work establishes a new model to compare MpT development across insects, and provides a framework to help understand how an evolutionary novelty – the cryptonephridial system – arose during organ evolution.
The permeability characteristics of the isolated malpighian tubules of the housefly Musca domestica
Comparative Biochemistry and Physiology Part A: Physiology
The permeability characteristics of the Maipighian tubules of Musca domesticci have been determined by measuring tubule Buid: bathing medium ratios for D-. Land CH,-glucose, inulin. dextrans and polyethylene glycols. 2. Molecules cross the epithelium in inverse relation to their molecular size, although the permeability to polyethylene glycols is independent of molecular chain length. 3. No correlation between tubule fluid: bathing medium ratio and rates of Ruid secretion is observed with CH,-glucose and polyethylene glycols, but an inverse relationship does exist for inulin and dextrans indicating a molecular sieving effect for these molecules. 4. The results are interpreted in terms of fluid flow occurring via the intercellular spaces with filtration across the tubule epithelium being linked with potassium secretion.
The Passive Permeability of Insect Malpighian Tubules to Organic Solutes
Journal of Experimental Biology, 1974
1. The permeability of Malpighian tubules of five insect species to a range of organic solutes has been measured by both in vitro and in vivo techniques. 2. Nearly all the substances tested were found, in in vitro experiments, to penetrate the walls of Malpighian tubules in a manner which, on several criteria, was judged to be passive. 3. The walls of Malpighian tubules are more permeable to small molecules than to large ones; but even inulin (MW 5200) penetrates fast enough to reach concentrations which, in tubules secreting fluid slowly, can be as high in the secreted fluid as 50% of its concentration in the bathing fluid. 4. Inulin injected into Schistocerca and L-fucose injected into Rhodnius appeared in the excreta at rates which could be accurately predicted from the in vitro behaviour of Malpighian tubules of these insects. 5. Taken with the fact that the cuticular lining of the rectum of insects is thought to be not very permeable, the high permeability of insect Malpighian ...
Peptides, 2011
Spined soldier bugs, Podisus maculiventris, are heteropteran insects that feed voraciously on other insects, particular the soft bodied larval forms of Lepidoptera and Coleoptera. The response of P. maculiventris Malpighian tubules (MTs) to serotonin and known diuretic and antidiuretic peptides has been investigated, and is compared with that of MT from the hematophagous and phytophagous heteropteran bugs Rhodnius prolixus and Acrosternum hilare, respectively. A CRF-related peptide diuretic hormone (DH) from the termite Zootermopsis nevadensis (Zoone-DH) stimulated MT secretion, which was reversed by a member of the CAP 2b family of peptides from A. hilare (Acrhi-CAP 2b-2), an antidiuretic effect. Serotonin had no effect on secretion, neither did a representative calcitonin-like DH, kinin, tachykinin-related peptide, and an antidiuretic factor from the mealworm Tenebrio molitor (Tenmo-ADFb) in both P. maculiventris or A. hilare. Serotonin is a DH in R. prolixus, and its lack of effect on MT from P. maculiventris and A. hilare suggests this is an adaptation to hematophagy. On the other hand, the antidiuretic activity of members of the CAP 2b family in all three bugs is consistent with this being a heteropteran feature rather than a specialism for hematophagy.
Gazi University Journal of Science, 2020
The excretory system in insects consists of Malpighian tubules (MTs) which are responsible for osmoregulation. The functions of the MTs are the removal of the last products of metabolism and the transfer of the toxic compounds into the hindgut. The MTs of the insects vary structurally. In this study, the MTs of Isophya nervosa Ramme, 1951, which is a species that belongs to Orthoptera order, were investigated by light and electron microscopes. Adult individuals of Isophya nervosa were collected in Kızılcahamam, Ankara in 2017 and 2018. Extracted MTs were fixed in Formaldehyde for light microscopy, in glutaraldehyde for electron microscopes. They were examined and photographed after dehydration, blocking, sectioning and staining processes were completed. This species has a great number of MTs. One end of the MTs in this species is attached to the ileum and the other closed end is free in hemolymph. The outer surface of the cells is surrounded by muscle layers and trachea. There are m...
The Malpighian tubules are responsible for excretion and osmoregulation in insects. The Malpighian system consists of tubules that are closed at the distal end and extend from the point of junction of the midgut and hindgut. This organ helps the water and electrolyte balance of the internal metabolism by filtration with absorption of water and soluble materials as mineral salts from the hemolymph. In this study, the histology of Malpighian tubules in Gryllus campestris (Orthoptera, Gryllidae) has been examined in detail by light microscopy, scanning electron microscopy, and transmission electron microscopy. The distal ends of the Malpighian tubules in G. campestris, which are long and wiggly in shape, extend freely into the body cavity. The other end is connected to the alimentary canal. In a cross-section of the tubules, it has been observed that the outer surface of the cells is covered by muscles and trachea. The lumen is lined with a single-layer epithelium. The nuclei (which are oval or spherical in shape), rough endoplasmic reticulum, mitochondria, and spherocrystals or mineral concretions are seen in the cells. Microvilli are found in the apical membrane. When the structure of the Malpighian tubules was compared with those of other species belonging to Orthoptera and other insect orders, similarities and differences were observed.
The Journal of Basic & Applied Zoology, 2014
The Malpighian tubules of pharate adult of Sarcophaga ruficornis lacks the characteristics of transporting epithelia with extremely thick basal lamina and absence of basal membrane infoldings. There is heavy vacuolation in the region of basal infoldings. The mitochondria, very often filamentous in nature, are abundantly found in the tubule cells, lying parallel towards the apical region and in the process of being inserted into luminal microvilli. All the luminal microvilli do not contain mitochondria; some of them are devoid of these structures. The central cytoplasm contains a prominent nucleus, a high density of mitochondria, lipid droplets, spherocrystals and multivesicular bodies. Outside the basal lamina, are found several tracheoles. The study supports the standing gradient hypothesis for fluid transport by Malpighian tubules.