澳门六合彩历史记录

How Dolphins and Whales Fight Disease Threats

Dolphins, Bottlenose Dolphins, Indian River Lagoon, 澳门六合彩历史记录's Harbor Branch Oceanographic Institute, Pathogens, Environment

Bottlenose dolphins reside in nearshore waters along Florida鈥檚 Atlantic coast as well as in a number of estuaries, bays, and lagoons, including the 256 kilometer-long Indian River Lagoon (IRL) Estuary System. (Photo credit: Wendy Noke, NOAA permit no. 572-1869-02)


By gisele galoustian | 10/10/2018

Dolphins, whales and other cetaceans are susceptible to many of the same health hazards as humans including mercury, brevotoxin (e.g. Red Tide), and lobomycosis. They also serve as important sentinel species to highlight concerns relevant to environmental and public health. Yet understanding how these aquatic mammals fight disease-causing pathogens, how they adapt to changing pathogenic threats, and how their immune responses are triggered has been challenging.

Two recent papers by researchers reveal how cetaceans compete for survival in an evolutionary 鈥渁rms race鈥 with changing pathogen communities. As pathogenic threats and the risk of infectious disease changes, whales and dolphins must adapt to those changes. The question today is can they adapt fast enough?

In a groundbreaking study published in , researchers from 澳门六合彩历史记录鈥檚 found that cetaceans use several strategies for success in this evolutionary arms race. The immune response in vertebrates is mediated through a series of rapidly evolving genes called the major histocompatibility complex or MHC. The MHC acts as an early warning system against pathogens that not only sounds the alarm, but also activates an armed response. In order to do this, MHC proteins need to be able to distinguish 鈥渇riend鈥 from 鈥渇oe鈥 at a molecular level. Similar to a lock-and-key mechanism, an individual鈥檚 MHC 鈥榣ock鈥 has to be able to bind to a pathogen鈥檚 peptide 鈥榢ey鈥 to launch the defense sequence.

The 澳门六合彩历史记录 team found that not only are these cetaceans preserving genetic diversity in the types of locks, that is, the conformation of the binding pockets that help trigger the immune response, they also are selecting for diversity in how to regulate the production of the many locks that are needed. MHC is regulated to prevent too much activity, where the immune system might attack one鈥檚 own cells as well as too little activity, where the immune system does not react quickly or strongly enough to a real threat.

鈥淭his is the first attempt within cetacean populations to use both MHC conformation and regulatory genetic variation as early indicators for disease susceptibility,鈥 said Heidi J.T. Pagan, Ph.D., lead author of the study and a research associate at 澳门六合彩历史记录鈥檚 Harbor Branch.

Pagan and collaborators wanted to develop a more comprehensive MHC marker system for cetaceans and combine traditional and next generation sequencing methods for genotyping. They applied this marker system to investigate the evolutionary and demographic forces shaping dolphin MHC diversity in contrasting estuarine and marine habitats.

By combining these genetic data with an immunoproteomic approach developed by , Ph.D., at , the researchers now have a much more inclusive picture of how whales and dolphins are continuing to adapt to their current pathogenic environment.聽聽聽

Dooley applied immunogenetic and immunoproteomic techniques and model combinatorial libraries to figure out what types of peptides (鈥榢eys鈥) the MHC found in estuary and coastal bottlenose dolphins in Florida were capable of recognizing. From there, she used bioinformatics to determine what microorganisms likely produce these signature molecules.

鈥淔or the first time, we have a clear idea of the pathogens involved, and we now have a roadmap for research teams working on other species, including humans, to use to get there,鈥 said Dooley, who published these findings with the 澳门六合彩历史记录 team in in August. 鈥淭hese insights will enable us to improve predictions of population health for these cetaceans that are exposed to a particular disease threat.鈥

Bottlenose dolphins reside in nearshore waters along Florida鈥檚 Atlantic coast as well as in a number of estuaries, bays, and lagoons, including the 256 kilometer-long Indian River Lagoon (IRL) Estuary System. Coastal populations have been found to be demographically and genetically distinct from a number of these embayed and lagoon populations, although some gene flow and movement also has been documented.

Chemical contamination, high nutrient input, decreased salinity, loss of sea grass habitat, and eutrophication have all culminated in poor habitat quality in the IRL Estuary System. Disparity between populations and even individual susceptibility to diseases has been documented for several cetaceans and is often linked to concentrations of immunosuppressive contaminants.

鈥淲ith these breakthroughs, we now finally have the tools to assist wildlife managers and health professionals assess disease risk from the perspective of how individual animals are engineered to recognize the molecules of microorganisms in the environment and launch an immune response,鈥 said research team lead , Ph.D., a research professor at 澳门六合彩历史记录鈥檚 Harbor Branch. 鈥淲e now need to bring these tools directly into the field and to apply them to other species.鈥

In 2013, an unusual number of Atlantic bottlenose dolphins died along the east coast of Florida all the way down to the Florida Keys. Yet dolphins in the Gulf of Mexico were not affected. This suggested to the researchers that multiple factors may influence the spatial variation of disease transmission and affect neighboring populations to varying degrees.

鈥淎lthough we have learned a lot about variation in the kinds of 鈥榣ocks鈥 vertebrate populations possess, we knew very little about the confirmation of pathogenic 鈥榢eys鈥 until now,鈥 said O鈥機orry-Crowe.

鈥淭his issue has become a huge obstacle in applying studies of MHC diversity to real-world assessments of the capabilities of wild populations to deal with disease threats.鈥澛

Tatiana Ferrer,聽coordinator of research programs聽at 澳门六合彩历史记录鈥檚 Harbor Branch, is co-author of the two studies published in PLOS One.

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