Survival of the Galapagos Sea Lion

June 29, 2013 — Immune systems of endangered Galapagos sea lions are in overdrive because of harmful activity by people, reveal scientists from the Zoological Society of London (ZSL).

The study shows that Galapagos sea lions (Zalophus wollebaeki) are more prone to starvation because of exposure to human influences like pets and pollution. These can impair the level of their immunity, making them less able to hunt and more likely to go hungry when food is scarce.

This research is published June 28 in the journal PLOS ONE.

Conservationists spent more than eighteen months on the Islands of San Cristobal, which is inhabited by humans, and Santa Fe, where there are no humans, dogs, cats, mice or rats. They tagged 60 Galapagos sea lions from each island and monitored their behaviour and physiology.

ZSL's Institute of Zoology Director, Professor Tim Blackburn says: "We are increasingly aware of the threats of infectious diseases to wildlife around the world, from amphibians in the tropics to the birds in British gardens. It is worrying that we are now potentially seeing such threats to sea lions in the supposedly pristine wilderness of the Galapagos Islands."

ZSL's Dr. Paddy Brock, author on the paper, says: "A tell-tale sign of an unhealthy sea lion is a thinner than normal layer of blubber, which is what we saw in the sea lions on San Cristobal. This was all the more notable as we didn't notice these patterns in sea lions on Santa Fe, where they live without the presence of people or pets.

Continued: http://www.sciencedaily.com/releases/2013/06/130629164735.htm

Long-lasting Chemicals May Harm Sea Turtles -Scientists are discovering that sea turtles are highly contaminated with industrial chemicals and pesticides - vie Herp Digest

By Brett Israel and Environmental Health News  | Thursday, March 14, 2013 | 2

From the moment they are born, sea turtles fight to survive. Buried alive, they dig themselves out and evade hungry crabs and birds as they crawl to the ocean, where they begin a long and treacherous migration. One out of 1,000 will survive into adulthood. And those that do will bear a toxic burden.

Scientists are discovering that sea turtles, long ignored by toxicologists who study wildlife, are highly contaminated with industrial chemicals and pesticides.

Loggerhead turtles have altered immune systems and smaller eggs that some studies have linked to contaminants. These chemicals kill turtle cells in lab experiments, and based on research in other marine life, scientists suspect that sea turtles may be vulnerable to thyroid, liver and neurological damage.

No one, however, knows the extent to which sea turtles in the wild may be harmed.

While other ocean creatures, including whales, seals and some fish, are well-studied, the chemical threats to sea turtles remain mostly hidden under a shell.

Decimated by climate change, poaching, accidental snaring and ocean trash, all U.S. species of sea turtles are protected by the Endangered Species Act, which makes studying them difficult.

"We really have just barely touched the tip of the iceberg," said Jennifer Keller, a marine biologist at the Hollings Marine Laboratory in Charleston, S.C. She is the top expert on pollution in sea turtles.

Sea turtles have some industrial compounds in their blood nearing levels that damage marine mammals. Keller's lab last year measured perfluorochemicals (PFCs) in the blood of five sea turtle species off the southeastern U.S. coast, and her calculations suggest that the turtles' potential risk for toxic effects is high.

Other long-lived chemicals also contaminate sea turtles, including polychlorinated biphenyls (PCBs), which are widely used industrial compounds banned in the late 1970s, and brominated flame retardants.

"These chemicals may not acutely poison the animals, but they can make exposed individuals a little more vulnerable to opportunistic infections or new and emerging infectious diseases," said Peter Ross, a research scientist in Canada who is one of the world’s leading experts on marine mammals and contaminants.

Some chemicals, particularly PCBs, have been shown to suppress the immune systems of wildlife, contributing to mass die-offs of seals and other marine mammals in the late 1980s and early 1990s.

This catastrophic damage hasn't been seen in turtles. Pollutants in their blood are orders of magnitude lower than levels in marine mammal blood, Keller said.

Nevertheless, Keller’s research with loggerheads caught off South Carolina has linked immune system changes to a variety of contaminants. As levels of chlordane and mirex – two pesticides banned in the United States decades ago but still in the environment – went up in the turtles, their production of some disease-fighting immune cells decreased. And as PCBs and the pesticide DDT went up, some of their immune cells increased.

"Any alteration of immune function, even enhancement, can be considered an adverse effect," the authors wrote. Enhanced immune responses can lead to autoimmune diseases and hypersensitivity.

"Exposure to even relatively low concentrations of persistent pollutants can reduce the effectiveness of immune defense against any number of pathogens," Ross said.

The chemical soup inside turtles comes from the food they eat, which varies from the crab-eating Kemp's ridleys, jellyfish-eating leatherbacks, omnivorous loggerheads, spongivorous hawksbills and herbivorous green sea turtles.

Persistent organic pollutants magnify every step up a food web to top predators such as dolphins, seals and sea lions. Killer whales are the most contaminated wild creatures on the planet. Sea turtles vary in their pecking order, and chemicals build up in them accordingly. Because some can live to 100 years old, they can accumulate  high levels of contaminants.

In leatherbacks, research has shown that some contamination is passed on to their eggs. PCBs and flame retardants correlate with smaller turtle eggs, according to a recent study by Keller. Research in birds has shown similar effects.

"If this is a cause and effect relationship, smaller eggs could lead to smaller hatchlings and reduced fitness," Keller said.

Young marine animals are most at risk. "It's in the young that we tend to see the most poignant evidence of effects, and those effects can be permanent," Ross said.

PFCs, used as water and grease repellants, have been found in humans and wildlife around the world. PFOS, or perfluorooctane sulfonate, produced by 3M and used in Scotchgard, was phased out in 2001, but remains the predominant PFC in the environment.

Keller found that PFOS was the main PFC in sea turtles, which is similar to what's found in other wildlife, said Craig Butt, an environmental chemist at Duke University.

"This is true whether you look at sea turtles off the coast of Georgia or polar bears in the Arctic," Butt said.

Concentrations of the five most abundant PFCs in these turtles are related to their different levels on the food web, with decreasing concentrations beginning with Kemp’s ridley, then loggerhead, leatherback and green turtles.

Hawksbill turtles, which are spongivores, have "surprisingly high concentrations of PFOS and PFCs," the researchers wrote in the study. Crab-eating Kemp's ridleys had even higher levels. The data support previous PFC measurements in Kemp's ridley and loggerhead turtles.

In dolphins and some other marine mammals, PFCs have been linked to damage to the immune system, blood cells, kidneys and liver.

"We know they're exposed, and we know at least for PFOS, sea turtles approach concentrations that cause thyroid and neurological disruptions and immune suppression [in mammals],” Keller said.

To see if the damage to reptiles mirrors the damage seen in mammals, Celine Godard-Codding, an environmental toxicologist at Texas Tech University in Lubbock, has been examining how turtle cells respond to PFCs. Preliminary data from her lab found that PFOA doses that are toxic to mammalian cells will also kill 80 percent of reptilian cells tested. More recent experiments with PFOS found similar results.

"So far turtle cells react identically to mammal cells," said Sarah Webb, the research project manager at Texas Tech.

The doses used are higher than those found in sea turtle blood. That's because PFCs build up in tissues, so an animal's cells will have more PFCs than its blood. No one has measured them in turtle tissues yet.

All five species of sea turtles in Keller's study were at risk for potential immune suppression, according to the researchers' estimated margins of safety. This calculation is based on effects seen in lab mice and rats. Regulatory agencies use these margins of safety to determine potential risk of toxic effects.

For the highly exposed hawksbills and Kemp's ridleys, the safety margins also put them at risk of liver, thyroid and neurobehavioral damage.

To learn more, Keller's lab is looking to the U.S. Pacific, where sea turtles haven't been tested for contaminants.

One hypothesis is that chemicals might be responsible for a virus, called fibropapillomatosis, that promotes the growth of tumors in the Pacific’s sea turtles. If chemicals suppress their immune system, the virus could grow into tumors.

But so far Keller has not found any evidence of that. "Our pilot study is showing that it does not look like organic contaminants are the trigger or cause," she said.

Since the 2001 phaseout of PFOS, levels have decreased in many marine animals. From 2000 to 2008, PFOS declined by 20 percent annually in loggerhead turtles tested near Charleston, S.C. Yet PFOS and its precursors remain in older consumer products, and sea turtles remain contaminated.

"PFOS is still out there in consumer products. It's still on couches and carpets," Keller said. "Eventually those things are going to go to the landfill. We need better ways to dispose of them."

This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.

Funding for Aberdeen research using shark immune systems to develop drugs

A team developing anti-cancer and anti-inflammatory drugs from research based on the immune systems of sharks has received a £1.5m funding boost.

The University of Aberdeen has received the financial backing to develop man-made proteins closely related to structures found in sharks.

Sharks are one of the most ancient species on the planet.

Scottish Enterprise and the Biotechnology and Biological Sciences Research Council awarded the money.

Structures called variable novel antigen receptors (VNARs) are found in the shark immune system.

Continued:  http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-21352836

Bats: A Good Immune System Ensures Success in Reproduction

ScienceDaily (May 16, 2012) — Anyone who is healthy has more enthusiasm for reproduction. The same is true even for bats. Male bats with a good immune system are more successful in being selected by females during mate choice and reproduction than their ailing counterparts, as recently highlighted by researchers of the Leibniz Institute for Zoo and Wildlife Research (IZW) in the online scientific journal PLoS ONE.

In male deer and peacocks we know: the more spikes in the antlers and the more eyes on the peacock's tail, the greater the success with females. The "good genes" hypothesis assumes that the attractiveness of males is associated with good genes passed on to offspring.

Now, for one specific version of the good genes hypothesis IZW-scientists found strong support. An IZW-team led by Simone Sommer and Christian Voigt demonstrated for lesser bulldog bats (Noctilio albiventris) that males with a high variability within the immune genes of the "major histocompatibility complex" (MHC), a gene region crucial for the immune defense against pathogens and parasites, reproduce better and hand on their good genes directly to the offspring. The likely reason for the higher reproductive success: Males with good MHC genes have to invest less energy into the defense against pathogens, particularly parasites.


Continued:   http://www.sciencedaily.com/releases/2012/05/120516195451.htm

The beasties we need near us, for our own sake

Courtney Humphries, contributor

In The Wild Life of Our Bodies, biologist Rob Dunn argues that our modern separation from other species causes more harm than good

THERE has been no shortage of nostalgia for the "good old days" of human prehistory, when our hunter-gatherer ancestors lived in ecological harmony with nature, roaming savannahs instead of cramped in office chairs. In The Wild Life of Our Bodies, Rob Dunn shares the view of modern human life as a paradise lost, but the loss he laments is not merely of a vague sense of being one with nature. What we have sacrificed, he argues, is a physical connection with the species that shaped our bodies - from our physique to the immune system.

As humans became urban and industrial, we also separated ourselves from other species. Pets aside, we have laboured to rid our houses and cities of creatures - not just visible predators and pests but also the microbes on our countertops and hands. Some of these steps were sensible acts of self-preservation, but others were driven by an ideology of humans as separate from nature. Dunn, a biologist at North Carolina State University as well as a science journalist, catalogues the dangers of that ideology.

To illustrate how species influence one another's evolution, he points to the pronghorn, a small antelope-like mammal in North America that runs inexplicably fast. The pronghorn's speed, Dunn says, only makes sense if you consider the large predators that once hunted it. The "pronghorn principle" also applies to the human body. We too are "haunted by ghosts" of parasites, pathogens and predators that shaped our evolution.
Dunn makes the case that the influence of these ghosts can be seen in our immune systems. He highlights early evidence suggesting that chronic inflammatory diseases of modern society, such as Crohn's disease, diabetes and asthma, could be alleviated by repopulating our bodies with the parasites we evolved with. Our bodies rely so much on gut bacteria that we even give them a safe house in the form of the appendix, Dunn points out, yet our love for antibiotics could be undermining this important relationship.

Dunn also highlights research that shows how we are shaped by the species we have eaten - and that once ate us. Our brains are still wired to avoid predators we no longer encounter: our adrenal system responds to modern daily stresses as if they were mortal threats, for example, and one theory holds that our acute vision may have evolved specifically to avoid venomous snakes. Meanwhile, as we domesticated plants and animals in our quest for survival, we too became domesticated, evolving the ability to drink cows' milk and break down the starch in grains more efficiently.

Dunn makes the case for these connections through detours and anecdotes, with lively stories of patients and scientists, and research spanning archaeology, field biology, medicine, ecology and microbiology. The elaborate fungus farms of leafcutter ant colonies, for instance, become a metaphor for understanding how we humans cultivate bacteria with our immune systems. By drawing connections between work that seems unrelated, Dunn repeatedly drives home his key point: we ignore the lessons of ecology at our peril. By trying to separate ourselves from nature, we have tricked ourselves into believing we are self-sufficient.

Looking for a better way forward, Dunn is practical. Rather than issue a blanket call for "more nature", he advocates applying the lessons of studying our own ecology. Instead of surrounding ourselves only with the plants and animals we find most appealing, we also need to be aware of creatures that help keep our instincts sharp, and species like worms and bacteria that keep our immune systems in check.

Dunn doesn't go so far as to suggest letting predators loose in Central Park, but he does argue for more diversity in the species we interact with and eat. As he writes, "What is missing from our lives is not nature, but a kind of nature that most benefits us".

http://www.newscientist.com/blogs/culturelab/2011/06/the-beasties-we-need-near-us-for-our-own-sake.html