Cna

h3c o

Pahutoxin 45

Figure 8 Chemical defense of fish.

of a surfactant but there is evidence that its strong ichthyotoxic effect is receptor mediated. The release of traces of such compounds in water is deterrent enough to prevent predators from attack.

The venoms of many fishes contain proteins that are very often labile and thus their characterization is complicated. The stingray (Potamotrygonidae) hides a powerful sting in its tail that it uses to wound aggressors and to introduce a proteinogenic poison. Often, fish use a combination of proteinous venoms together with neuroactive small molecules such as acetylcholine (e.g., Pterois volitans, firefish) that act synergistically.

Pufferfish (Tetraodontidae) are famous for the extremely toxic tetrodotoxin 34 that blocks sodium channels and leads to death quickly (LD50 (human) 10 mgkg-1). This poison is produced by symbiotic bacteria

(see Marine and Aquatic Defense Strategies). Apparently, some fishes evolved resistance against powerful toxins such as tetrodotoxin 34, saxitoxin 4, palytoxin 44, as well as polyether toxins (see previous discussion on ciguatera), which allows them to feed on producing organisms and to accumulate their toxins as weapon against predators (see discussion on sequestration in Animal Defense Strategies).

Was this article helpful?

0 0
Trash To Cash

Trash To Cash

This book will surely change your life due to the fact that after reading this book and following through with the steps that are laid out for you in a clear and concise form you will be earning as much as several thousand extra dollars a month,  as you can see by the cover of the book we will be discussing how you can make cash for what is considered trash by many people, these are items that have value to many people that can be sold and help people who need these items most.

Get My Free Ebook


Post a comment