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Rotary Happenings: Connecting cone snails, tennis rackets and pain medications

February 13, 2019
Island Reporter, Captiva Current, Sanibel-Captiva Islander

Every Friday before leaving my home for our weekly Sanibel-Captiva Rotary Club meeting, I check out who is going to be our speaker that morning. This past week, the speaker's name was not familiar nor after reading the speaker's topic was I aware of what we were going to learn about that morning. The topic was "Cone snails, tennis rackets, and pain medications - A Mollusk's Story." Oh, my. Well, the speaker was Dr. Tom Annesley and quite familiar to many people on the island, since he is the president of the Sanibel-Captiva Shell Club and an important member of the volunteer educational team at the Bailey-Mathews National Shell Museum.

Annesley does public lectures at the museum, leads beach walks, and docents at the live shell tank at the museum. He is an active professor emeritus at the University of Michigan and deputy editor of the journal "Clinical Chemistry." Annesley has always had an interest in oceanography and spent summers in California, where his uncle dropped him off at the costal tide pools on his way to work and then picked him up on his way home. Annesley has an astounding resume with degrees and educational appointments in the areas of pathology, clinical chemistry in pathology, biochemistry, and drug analysis and toxicology, and this all has, to an extent, a connection to his topic of the day.

How many islanders have collected cone shells on our island beaches? How many of you know that live cone shells/cone snails are venomous and some of their species can exude a toxic poisonous venom that can kill humans? Well, I really had no idea until Friday morning. Before I get too deep into this, I want to say the cone snails in our local waters are not the highly venomous ones, but live ones can sting you and cause discomfort - handle with care. There are about 700 species of cone snails, marine gastropod molluscs/mollusks.

Article Photos

Dr. Tom Annesley, president of the Sanibel-Captiva Shell Club, was the guest speaker at the Sanibel-Captiva Rotary Club's recent meeting.

Annesley showed us a short video clip of a highly venomous live cone snail and the speed at which they can attack and paralyze their prey and then devour them. Cones feed on worms, mollusks, or small fish. Those that eat worms have the weakest venom - our local cones eat marine worms - but those that eat fish and mollusks can produce highly venomous toxins. When watching the video, one watches a harpoon-like long-extending proboscis project from the cone and in a split nanosecond inject venom into its prey causing it to seizure and then become paralyzed. The fish is draw to the cone shell/cone snail by withdrawal of the harpoon-like proboscis to the mouth of the cone and devoured. A cone snail itself moves slowly and this process of projecting its venom out through this method allows them to capture food quickly.

Going back to the subject outlined for the morning, the next topic listed was tennis rackets. Cone snails, tennis rackets - I didn't get an immediate connection. Well, there really isn't a direct connection between cone snails and tennis rackets, but indeed a connection with seashells; crushed seashells of all kinds to be exact. Philippine born scientist Baldomero "Toto" Olivera spent a great deal of time around the tennis courts where his father played tennis in the Philippines. He loved the shells and had a great deal of time to study them. Later in the states, Olivera's college graduate studies included studies of the predatory Conus/cone snails each having unique venoms and neurological responses in prey. In the lab the study included peptide toxins that induced neurological responses. Studies further included how these peptides could be used to treat humans for blocking pain and other nervous system functions.

Cone snail venom studies are leading pharmaceutical companies to explore the potential of cone snail peptide toxins in the field of medicine. Ziconotide (Priait), a pain reliever 1,000 times as powerful as morphine, was initially isolated from cone venom. The usage of isolated cone peptide toxin compounds are leading medical studies for use for Parkinson, Alzheimer's, depression and epilepsy. Other studies are being conducted for use for post-surgical and neuropathic pain.

Something so seemingly harmless as a beautiful seashell can hold a sea creature that produces deadly toxins that can kill in a flash, but that same toxin can save the quality of life for so many humans. Nature is a true wonder and the endless possibilities that can be derived from the study of nature are boundless. Another lesson here is, let your kids explore nature, encourage their curiosity about nature, and who knows what might come of it. Annesley and Olivera were two kids who had that opportunity and see what happened.

For information about the Sanibel-Captiva Rotary Club, visit or The club meets every Friday at 7 a.m. at the Dunes Golf and Tennis Club, at 949 Sand Castle Road, Sanibel; visitors are welcome to attend.



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