These granules or spheres, ranging in size from 0.14 to 10.8 µm diameter, are found on the chorion of many spider species and differ in their shape, density, and distribution among different species. Spider eggs are spherical and their chorion is covered by granules. The liquid that covers the eggs during oviposition dries onto the chorion and gives the egg surface a granular appearance. The egg mass is then covered by one or more layers of silk. Standing beneath the disc, the female extrudes a viscous liquid into which the eggs are laid and adhere to one another and to the basal disc. During construction of the egg-sac, the female first produces a silk platform. The egg-sac consists of layers of silk that form a barrier between the embryos and the outer world, but other components inside the egg-sac may also be involved in protection. Spider eggs are usually physically protected by the egg-sac. geometricus was also found to be toxic to mice, but it is not known if the eggs are toxic also to insects or microorganisms. Intravenously injected extract of eggs of L. For example, the eggs of the black widow spider, Latrodectus tredecimguttatus, contain toxic proteinaceous components, including the neurotoxic protein Latroeggtoxin-I, the sodium channel-inhibiting protein Latroeggtoxin-II, the insect-specific toxin Latroeggtoxin-III and the antibacterial peptide Latroeggtoxin-IV.
Yet, we are still far from understanding the overall strategies of antimicrobial defences of terrestrial arthropod eggs.īacterial contamination of spider eggs has not been documented in the literature, suggesting that there might be specific mechanisms to protect their eggs from pathogenic bacteria. Lysozyme was isolated from eggs of the Mediterranean fruit fly, and the antimicrobial protein sapecin was found in eggs of flesh flies.
#Blue spheres suspended in japanese liquid free
Female ixodid ticks protect their eggs by covering them with a waxy substance, which contains at least two antimicrobial free fatty acids. isolated an antibacterial peptide from the eggs of the Mediterranean fruit fly Ceratitis capitata. Eggs of terrestrial invertebrates are often laid on or in the soil, where they are exposed to harmful soil microorganisms. Various types of molecules are known as antimicrobial agents in eggs of marine invertebrates, such as indole derivatives, free fatty acids, lysozymes and glycoproteins. Eggs of marine invertebrates appear to have broad-spectrum antimicrobial activity. Understanding the properties of these unique structures may contribute significantly to our knowledge of how nature deals with bacterial infections.ĭuring the last few decades, most research dealing with antimicrobial characteristics of invertebrate eggs focused on marine invertebrates. Egg surface roughness and hydrophobicity combined with its antibacterial chemical properties reduce the ability of bacteria to grow on the egg surface. In this study, we demonstrate that the egg surface is hydrophobic, while the spheres are superhydrophilic. The spheres are rich in low-molecular-weight proteins, yet their exact composition remains unknown. The source and characteristics of this antibacterial activity are distinctive and stem in part from a dense layer of spheres covering the egg surface, likely originated from the oviposition fluid. The defence strategy against bacterial invasion was demonstrated in the whole egg, whole egg extract, egg surface extract, eggshell and eggshell extract. Antibacterial activity was shown by inhibition of bacterial growth on agar plate, liquid culture and retarded biofilm formation.
In this article, we elucidate the defence strategy of brown widow spider ( Latrodectus geometricus) eggs against bacteria. Several defence mechanisms have evolved to protect the developing embryos against microbial threats. Eggs provide a rich source of nutrients for the developing embryo, making them a favoured food source for other organisms as well.
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