Dengue virus comes in four subtypes. Fighting off a first dengue infection increases the risk for developing a more severe form of dengue fever if they are infected a second time with a different dengue virus subtype. Dengue virus leverages the immune system to its advantage. Enhancing developing countries’ scientific and clinical infrastructure can help the international effort to counter the spread of dengue.

The Virochip has been used to identify the infectious agents of SARS and other diseases. When the Virochip alone is not enough, new DNA sequencing technologies have been used to sequence all the nucleotides in the sample. Bioinformatic tools can then identify those sequences that are of viral origin. Recent advances in sequencing technology suggest that personal genome sequencing could become routine in the not too distant future.

Mosquitoes are vectors for many viral diseases including dengue fever and West Nile. Understanding how a virus infects the mosquito is important in understanding how the disease will spread. On Grand Cayman, transgenic mosquitoes have been used in an effort to eradicate the mosquito vector. This discussion explores the ethics of genetically-modified organisms and other topics.

Natural selection has produced an astounding array of venoms for prey capture. Marine cone snails are among the most dangerous venomous creatures. Cone snail venoms are potent, deadly to fish and people, and each species makes a venomous cocktail of up to 200 different toxins. One of these toxins has been developed into a drug called Prialt–a pain killer that prevents the spinal cord from relaying pain information to the brain. With over 700 living species of cone snails, each having up to 200 unique toxins, there are potentially more than 140,000 novel molecules with drug potential.

Bacteria live in and on us in complex communities that outnumber the cells and genes of our own tissues. These bacteria possess a communication mechanism that allows them to coordinate their activities. This mechanism, called quorum sensing, was first described in bacteria living symbiotically in a squid. The bacteria produce bioluminescence which simulates moonlight and camouflages the squid. The key to quorum sensing is a molecular signal released by the bacteria that is monitored by receptors, which in turn modulate gene expression. Bioluminescence genes are only turned on when the population density–and therefore the signal concentration–is high.

Cone snail venoms have a wide variety of effects, ranging from convulsive shock, to paralysis, to sedation. The venoms contain a mixture of peptide toxins that simultaneously attack different molecular targets of the nervous system. The evolution of such a diversity of toxins is made possible by multiple gene superfamilies containing hypervariable sequences. The research and medical value of a group of animals like the cone snails is a powerful reminder of what we can learn from biodiversity. Venomous relatives of the cone snails–the turrid snails–number over 10,000 known species, representing a million compounds of potential pharmacological value.

Pathogenic bacteria use quorum sensing to launch a simultaneous attack when in sufficient numbers. Bacteria possess at least two systems of quorum sensing. They sense their own species' numbers by monitoring their species-specific quorum sensing signal. Bacteria also sense a signal that is shared between different species to obtain information about the bacterial community. Manipulating quorum sensing is a promising approach for developing new antibiotics against pathogens, or probiotics for industrial applications.

Questions on biodiversity, endangered habitats, and how best to preserve the Earth's ecosystems, are answered by Dr. E.O. Wilson of the Department of Organismic and Evolutionary Biology at Harvard University, Dr. Eric Chivian of the Center for Health and the Global Environment at Harvard Medical School, Dr. Bassler and Dr. Olivera. Drs. Wilson and Chivian deliver short presentations on biodiversity to start the session. The question and answer session is moderated by HHMI President Dr. Robert Tjian.

Dr. Bonnie Bassler discusses antibiotics development, quorum sensing, and other topics related to bacteria in a question-and-answer session with a student audience.

Dr. Baldomero Olivera discusses various aspects of the biology of the venomous cone snails in a question-and-answer session with a student audience.