Related Experiment Video
Updated: Jul 30, 2026
12:06
Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines
Published on: November 25, 2017
Mechanism of mannose toxicity
Biochemical and Biophysical Research Communications
|October 15, 1986
Summary
Mannose is toxic to honeybees due to low mannosephosphate isomerase, causing ATP depletion. Other insects are resistant, suggesting a hexosephosphate accumulation mechanism for mannose toxicity.
Area of Science:
- Biochemistry
- Insect Physiology
- Toxicology
Background:
- Mannose toxicity affects honeybees, leading to ATP depletion.
- Enzyme levels, specifically mannosephosphate isomerase and hexokinase, vary between sensitive and insensitive insects.
Purpose of the Study:
- To investigate the biochemical mechanism of mannose toxicity in honeybees.
- To compare the enzymatic basis of mannose sensitivity in honeybees versus other insect species.
Main Methods:
- Enzyme assays were performed to quantify mannosephosphate isomerase and hexokinase levels.
- Toxicity of mannose and 2-deoxyglucose was assessed in honeybees and other insects.
Main Results:
- Honeybees exhibit a shortage of mannosephosphate isomerase, leading to mannose-6-P accumulation and ATP depletion.
- Drosophila melanogaster and Ceratitis capitata are insensitive to mannose and possess higher mannosephosphate isomerase relative to hexokinase.
- 2-Deoxyglucose shows toxicity similar to mannose in honeybees and other insects.
Conclusions:
- Mannose toxicity in honeybees is linked to insufficient mannosephosphate isomerase activity.
- The accumulation of hexosephosphates is a key factor in mannose-induced toxicity across studied insects.
Related Concept Videos
01:24Oligosaccharide Assembly
Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
Multiple sugar molecules that may or may...
01:32Export of Misfolded Proteins out of the ER
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
01:05Proteoglycans
Glycans, a class of complex heterogeneous molecules, can be covalently attached to proteins to form glycosylated proteins that regulate various physiological and pathological processes. Glycosylated proteins or glycoproteins comprise N-linked and O-linked oligosaccharides. O-glycosylation is the most common type of protein glycosylation. Here, glycans attach to the oxygen atom of the hydroxyl groups of Serine or Threonine residues. O-linked glycosylation occurs later in protein processing,...
01:19Overview of Carbohydrate Metabolism
Carbohydrate metabolism is a fundamental biochemical process that ensures a constant supply of energy to living cells. The most important carbohydrate is glucose, which can be broken down via glycolysis to enter into the Krebs cycle and eventually lead to the production of ATP through oxidative phosphorylation.
Glucose transport into cells is facilitated by a family of transport proteins called GLUT (Glucose Transporters). GLUT4 is the primary glucose transporter for insulin-stimulated glucose...
Glucose transport into cells is facilitated by a family of transport proteins called GLUT (Glucose Transporters). GLUT4 is the primary glucose transporter for insulin-stimulated glucose...
01:25Mechanism of Antibiotic Resistance in MRSA
Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
01:26Bacterial Meningitis II: Pathophysiology
Bacterial meningitis typically begins when pathogens such as Neisseria meningitidis and Streptococcus pneumoniae colonize the nasopharynx and invade the bloodstream. This process is facilitated by bacterial virulence factors, such as polysaccharide capsules, which resist phagocytosis and complement-mediated killing. Less commonly, bacteria reach the central nervous system via contiguous spread from infections like otitis media or sinusitis, through congenital or acquired dural defects, or...