Worrisome & Wonderful

Research on cyanobacteria is being carried out worldwide with toxins produced in Wayne Carmichael's lab at Wright State University.

Health officials urgently requested help and information through the Internet. A self-proclaimed "witch" prescribed an herbal tea. National media noted that a key health secretary was unavailable, vacationing in Europe at the time. The situation became hotly political, and accusations mushroomed.

Carnival time was ending in Rio de Janeiro as Sandra Azevedo watched television reports and pieced together details of the tragedy to the north. Early finger pointing at water chlorination processes did not match with what she had learned under Wayne Carmichael's tutelage at Wright State University. The Federal University professor recognized the symptoms of cyanobacteria toxin poisoning and contacted state health officials with her suspicions.

With the government's support, she tested samples taken from the reservoir that supplied Caruaru's water. Brazilian authorities enlisted aid from the Centers for Disease Control (CDC) in Atlanta. Samples sent to Carmichael, professor of biological sciences and a leading expert on blue-green algae (known to scientists as cyanobacteria), at his Wright State lab confirmed Azevedo's suspicions. Patterns identical to those found in previous laboratory animal experiments were found as Carmichael unraveled the cause of the first known human deaths attributable to the toxins found in cyanobacteria. At the request of the Brazilian federal government, Carmichael hurried from Ohio to the small town, 75 miles from Recife, capital of the state of Pernambuco.

In Caruaru, Carmichael drove over the narrow, hilly, cobblestone streets which locals traveled mostly on foot or in donkey carts. There, he toured the modern dialysis clinic, built to international standards. Without the benefit of piped-in water, the dialysis clinic, like many businesses and residences, relied on water collected at the city's reservoir prior to the sand filtration system and transported by tanker truck where it was chlorinated. This water was to receive further, more specialized treatment, at the dialysis center's in-house facility.

"Without the full benefit of the water treatment plant, this water contained high levels of toxins which were not removed by the small, inadequately maintained, in-house treatment facility of one of the hemodialysis centers," explains Carmichael. Although two of the centers were new, and one had only been open a couple of months, the water treatment facility at the center where people died was in a state of neglect.

"This was not an ecological accident or stroke of misfortune as some have argued. It is possible to prevent contamination of this kind by taking steps to control water quality," Carmichael says. He and Azevedo continue to work on investigating committees with the Brazilian government and state officials. Carmichael is also organizing seminars on the problems of liver disease and hemodialysis in cooperation with the Centers for Disease Control in Atlanta, and the state health authorities of Pernambuco.

There are several lines of guilt in this tragedy. Were responsible monitoring procedures in place? If water was analyzed, it wasn't done on-site, but in the capital of Recife and involved significant delay. Was water treatment inadequate? Did privately owned clinics have people with the appropriate training, background, and experience needed to operate them? Was there criminal neglect?

"Ultimately, the CDC stated, you have a first-world technology - dialysis - placed in a country that can't support it," says Carmichael. "It has brought the problem of blue-green algae to international awareness at the expense of a significant tragedy. It is unfortunate that information (about blue-green algae) was not known widely enough to prevent the problem in the first place."

A Fascination With Things Microscopic

The incident in Caruaru, Brazil, brought Carmichael's work at Wright State University full circle. For more than 25 years he has applied himself to the basic science and research of cyanobacteria and could now use his knowledge to solve a practical, albeit tragic, problem. As a botany major at Oregon State University in the late '60's, Carmichael said he had "the young student's usual fascination with the microscope and things microscopic." He was also intrigued by the question of how toxins - naturally produced poisons - damage the body. "I decided to pursue both of my interests by looking into the production and action of poisons made by cyanobacteria."

In 1970, Carmichael became a graduate student of Paul R. Gorham, a professor at the University of Alberta in Edmonton. Twenty years earlier, Gorham was among the first scientists to study the properties of cyanobacteria, then known as blue-green algae, and had laid the groundwork for research that was underway in South Africa, Australia, and the United States.

"When I joined Gorham's group, cyanobacteria were typically referred to as blue-green algae because of the turquoise coloring of most blooms and the similarity between the microbes and true algae (both carry out photosynthesis)," Carmichael says. "But since then, we have established that what we called blue-green algae actually belong to a variety of cells called prokaryotic - those bearing the characteristics of bacteria. They have no membrane enveloping their nuclear material and usually lack membrane-bound material in their interior. Blue-green algae is now recognized as a major group of bacteria."

Today, there is not only international recognition of the problems of cyanobacteria, there is international recognition of Carmichael's work in the area. Wright State's 1995 Brage Golding Distinguished Professor of Research, Carmichael can effortlessly name 18 countries that have sent scientists to study with him in his lab. "There are about 30 labs in the world studying cyanobacteria. Of those, the labs in Brazil, Japan, China, and several European countries all got their start here at Wright State," he says.

The arrangements are reciprocal and Carmichael has done field work in most of the countries he names. He has held visiting faculty appointments at universities in Scotland, Norway, Finland, China, the former USSR, Portugal, and Brazil. In October he attended a symposium at the University of Tokyo to commemorate the Toyo Suisan Endowed Chair in Marine Biotechnology, an honor he held in 1993.

If the scientific community interested in the blue-greens seems far-reaching, it is because cyanobacteria themselves live almost everywhere. They can be found in waters from the equator to the arctic, in snow fields and in hot sulfurous pools, and in soil, wet or dry. "The toxins produced by cyanobacteria have been implicated in incidents occurring in virtually every corner of the earth," says Carmichael.

Cyanobacteria, responsible for the deaths of 55 Brazilians, are described by Carmichael as "toxins both worrisome and wonderful." They are pursued by researchers worldwide because of both their deadly properties and their potential power.

Cyanobacteria were among the earliest life forms and have provided insights into the origins of life. Fossil records show them present three and a half billion years ago. The first organisms able to carry out photosynthesis, "they undoubtedly played a major part in the oxygenation of the atmosphere," says Carmichael.

Both deadly and potentially valuable, the poisons produced by cyanobacteria fall into two groups defined by the symptoms they produce in animals.

The secondary chemicals produced by cyanobacteria, unlike those of any others produced by plants or animals, have anti-bacterial, anti-fungal, and anti-algal properties, and are deadly to mammals. It is these properties that hold the interest of Carmichael and other researchers. "Ours is one of the main labs for the isolation and growth of these chemicals," says Carmichael, who provides assistance to other labs and public health agencies in the isolation and culturing of the organisms. Scientists hope to apply what they learn from cyanobacteria and its secondary chemicals to the production of new drugs to treat cancer, liver disease, and Alzheimer's disease. Research is also being done into ways of channeling the power of the chemicals into safer pesticides and fertilizers. Both deadly and potentially valuable, the poisons produced by cyanobacteria fall into two groups, defined by the symptoms they produce in animals.

The neurotoxins disrupt communication between neurons and muscle groups. This interference with the functioning of the nervous system can lead to paralysis of the respiratory muscles and death within minutes. They account for the poisoning of some livestock in the United States, and Carmichael suspects that outbreaks of human gastroenteritis have resulted from blue-green toxins in drinking water.

Among the neurotoxins are anatoxin-a and anatoxin-a(s), both of which are unique to cyanobacteria. Researchers are exploring anatoxin-a with hope that a modified version might one day be administered to slow the mental degeneration of Alzheimer's disease. Anatoxin a(s) could, in theory, form the basis for more biodegradable and safer pesticides. Investigators seek to design a compound that would minimize accumulation in tissues of vertebrates but continue to kill agricultural pests. "Cyanobacterial neurotoxins, then," says Carmichael, "are both deadly and potentially valuable, but they are not as ubiquitous as the other major class of cyanobacterial poisons, the hepatotoxins. Hepatotoxins have been implicated in incidents occurring in virtually every corner of the earth." Research on hepatotoxins is being carried out worldwide with toxins grown and supplied by Wright State. Studies are directed primarily at understanding how the compounds affect the body and have uncovered disturbing evidence that human exposure to nonlethal doses of the hepatotoxins might contribute to the development of cancer.

Carmichael and a group of scientific colleagues just completed a three-year study of people in China who are repeatedly exposed to the toxins in their drinking water. "We suspect that the extraordinarily high rates of liver cancer in parts of China may be tied to the cyanobacterial hepatotoxins in the water. "It seems reasonable to guess that repeated low-level exposure to the toxins could favor the development of chronic disorders of the gastrointestinal tract and liver. If cancer and other chronic illnesses are indeed a danger, then drinking water supplies may need closer monitoring in many places," he says.

The American Water Works Association Research Foundation has given Carmichael a two-year grant to test selected water samples for toxins. Samples from North American water treatment plants serving communities of 5,000 to several million people are sent to Wright State in a study of algae-related toxin taste and odor problems. The foundation will correlate their water treatment programs with Carmichael's findings.

Eating blue-green algae from natural lakes and cultured algae farms is increasingly popular among health food devotees.

Carmichael recently became involved in a two-year study originated by the Lake Erie Protection Fund. The sale of Ohio's specialty license plates with lighthouses funds the project, which is investigating the impact of cyanobacteria on the food chain in Lake Erie. Some believe the recent proliferation of cyanobacteria, which began two years ago, may be the result of the introduction of zebra mussels to Lake Erie. The mussels may have altered the food chain, creating conditions conducive to the blue-greens. Cyanobacteria, which are not a good food source and which produce toxins, are considered a nuisance because of the surface scum they create. "Both times we tested blue-green algae in Lake Erie, they were toxic," says Carmichael. They may prove fatal to fish, waterfowl, and livestock in the area.

Despite the toxicity of the chemicals produced by cyanobacteria, eating blue-green algae from natural lakes and cultured algae farms is increasingly popular among health food devotees because of its high protein content. Carmichael expresses concern that the products be monitored to ensure that they are nontoxic. "Because cyanobacteria are often collected from the surface of an open body of water and because neither sellers nor buyers can distinguish toxic from nontoxic strains without applying sophisticated biochemical tests, the safety of these items is questionable," says Carmichael, who does quality-control testing of blue-green algae when it is harvested for the commercial algae industry. The state-funded research lab at Wright State has occasionally been retained by the industry to present independent confirmation that their algae products are nontoxic.

"All told, cyanobacteria constitute a small group of perhaps 500 to 1,500 species," he said. "But their power to harm and to help animals and humankind is great. Investigated and exploited responsibly, they can provide valuable tools for basic research in the life sciences and may one day participate in the treatment of disease."