Malpighian tubules are specialized structures found in the digestive systems of many arthropods, including most insects, which handle excretion and osmoregulation. The tubules are typically arranged in pairs and have a convoluted structure that increases their surface area.
Malpighian tubules extend from the digestive tract, typically the area between the midgut and hindgut, into the hemolymph—a mixture of blood and interstitial fluid found in insects and other arthropods, as well as most mollusks. Unlike other excretory systems, the excretory processes of Malpighian tubules lack a filtration step. Metabolic wastes, like uric acid, diffuse into the tubules from the hemolymph. The tubules are lined with a layer of transport epithelia. These specialized epithelial cells contain pumps that actively transport ions, like sodium (Na+) and potassium (K+), from the hemolymph into the interior of the tubule, called the lumen. Osmosis allows water to follow ions into the tubules passively. From the tubule lumen, water, ions, and waste travel from the intestine to the rectum. Tiny, protruding microvilli lining the inside of the tubules help maximize solute-water coupling and the propulsion of uric acid crystals through the tubules. In the rectum, specialized glands pump many of the ions back into the hemolymph. Osmosis …
Optical Quantification of Intracellular pH in Drosophila melanogaster Malpighian Tubule Epithelia with a Fluorescent Genetically-encoded pH Indicator
Organisms must keep bodily fluids at a constant temperature and pH while maintaining specific solute concentrations in order to support life functions. Osmoregulation is the process that balances solute and water levels.
Osmosis is the tendency of water to move from solutions with lower ion concentrations, or osmolarities, to those with higher ion concentrations. Osmosis occurs in response to differences in the molecular concentrations of solutions separated by a semipermeable membrane. Bodily fluids, which are separated by such membranes, contain water, non-electrolytes, and electrolytes—solutes that dissolve into ions in water. Both electrolytes and non-electrolytes influence osmotic balance. However, since the more important factor to osmosis is solute number, rather than size, the contribution of electrolytes is more significant. Unlike water, electrolytes cannot diffuse passively through membranes but rely on facilitated diffusion and active transport. In facilitated diffusion, protein-based channels move solutes across membranes. Conversely, energy is used to move ions against concentration gradients in active transport. When animals ingest food, material that cannot be used is excreted from the body. Excretory systems in nature involve tradeoffs between conserving energy and water. Nitrogen is among the most significant …
Protocols for Investigating the Host-tissue Distribution, Transmission-mode, and Effect on the Host Fitness of a Densovirus in the Cotton Bollworm
1State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 2Tobacco Research Institute, Chinese Academy of Agricultural Sciences, 3Crop and Environment Sciences, Harper Adams University
1Graduate School of Science, Kyoto University, 2Graduate School of Science, Osaka City University, 3The Hakubi Center for Advanced Research, Kyoto University, 4Graduate School of Environmental Science, Hokkaido University
Disclosing Hemolymph Collection and Inoculation of Metarhizium Blastospores into Rhipicephalus Microplus Ticks Towards Invertebrate Pathology Studies
1Post-Graduate Program in Veterinary Sciences, Federal Rural University of Rio de Janeiro, 2Department of Animal Parasitology, Federal Rural University of Rio de Janeiro, 3Department of Epidemiology and Public Health, Federal Rural University of Rio de Janeiro
Use of a Recombinant Mosquito Densovirus As a Gene Delivery Vector for the Functional Analysis of Genes in Mosquito Larvae
1Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, 2Reproductive Medical Centre of Guangdong Women and Children's Hospital
1Department of Biology, New Mexico State University, 2Department of Molecular Genetics and Microbiology, Duke University, 3Department of Computer Sciences, New Mexico State University, 4Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 5Institute of Applied Biosciences, New Mexico State University
1Microbiology and Pathogenesis Activity, Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 2Tick-Borne Diseases Activity, Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention