Gunther S. Stent, a UC Berkeley molecular biologist who was a member of the key postwar group of scientists who solved the basic mysteries of the gene and how DNA functions, died June 12 at a retirement home in Haverford, Pa.
He was 84 and died from a massive staph infection that he had been fighting for several months.
Possessed of a restless intellect, Stent changed career directions at least twice, first abandoning molecular biology for the study of neurology and behavior -- becoming a leading expert on leeches in the process -- then becoming a noted historian and philosopher of science.
"Gunther is one of the leading intellectuals of the era, one of the last generalists," language and behavior expert John Searle of UC Berkeley said at a 2005 symposium honoring Stent. "He is a Renaissance man."
Stent himself had a simpler explanation: "I have a very short attention span. I get bored very quickly."
Stent was a member of the so-called phage group, a cluster of notable scientists centered on Max Delbruck of Caltech. Other members included Francis Crick, Renato Dulbecco, Alfred Hershey, Salvador Luria and James Watson.
All shared the view that bacteriophages -- tiny viruses that infect only bacteria -- provided the simplest model for studying the intricacies of DNA.
Stent got his introduction to phages when he visited Delbruck in 1948 in an effort to become a postdoc in his laboratory. The noted biologist offered him a position, asking if Stent wanted to work on phage.
"Yes, sir," Stent replied. "That's exactly what I want to work on, but could you refresh my memory as to just what phage is actually all about?"
At Caltech, he worked alongside Watson before the latter's move to Cambridge University, where he and Crick deciphered the structure of DNA.
Stent had no major scientific breakthrough of his own, but his work helped prove the structure deduced by the Cambridge pair.
In one series of experiments, for example, he incorporated radioactive phosphorus into the DNA of a phage. When the isotope decayed into sulfur, it would break the DNA chain, killing the phage.
By correlating the rate of phosphorus decay with the loss of phage activity, he demonstrated that DNA was double-helical, confirming Watson and Crick's structure, said Michael Botchan, co-chairman of Berkeley's department of molecular and cell biology.
Stent's work on phage led to one of his most influential books, "Molecular Biology of Bacterial Viruses" (1963), which became the key text in the field.
An updated version in 1970, written with Berkeley colleague Richard Calendar and called "Molecular Genetics," is considered a classic.
From his arrival at Berkeley in 1952, he helped reshape the study of biology on the campus, playing a key role in the formation of the department of virology in 1957, the department of molecular biology in 1964 and the department of molecular and cell biology in 1987. He was chairman of the latter two from 1980 until 1992, a period in which the biology faculty grew from 15 members to 90.
In 1972, he told his wife that he was "bored with molecular biology" and took a sabbatical leave to Harvard University to study neurobiology. He turned to the leech as a simple model system, hoping to learn how the chemistry of the brain governed behavior and learning.
Always humble, he noted that if Francis Crick -- who also had turned to the study of behavior -- was unable to figure it out, it was not likely that he could.
"One of his most-cited papers was a proposed model for how learning takes place at the synapses of nerve cells," said Berkeley neurobiologist David Weisblat.
That 1973 paper still influences scientists, he said, but others of Stent's theories have fallen by the wayside.
"Gunther was famous for being wrong about stuff," he said. "He loved ideas, whether they were right or wrong, as long as they led to discussion and new ideas or experiments."
Stent established a leech colony in Albany, Calif., exporting thousands of leeches to researchers around the country and using the proceeds to fund his own research. The work led to the discovery of a new anti-coagulant called hementin. Stent and his assistant Roy T. Sawyer also discovered orgelase, a product used to treat glaucoma.
In the fall of 1982, the spraying of herbicides near the leech farm led to its almost complete destruction.
By then, Stent had turned to philosophy, writing a series of books that included "Paradoxes of Free Will" (2002), which won a major award from the American Philosophical Society. He also published books on morality as a biological phenomenon, prematurity in science and the end of biology.
Gunter Siegmund Stensch was born March 28, 1924, in Berlin. In his 1999 self-published autobiography, "Nazis, Women and Molecular Biology: Memoirs of a Lucky Self-Hater," he describes himself as a self-hating Jew who longed to join the Hitler Youth.
Instead, he fled Germany in 1938 to join his sister in Chicago, becoming a naturalized citizen in 1945, when he legally changed his name to Gunther Stent.
He enrolled at the University of Illinois and earned a bachelor's in chemistry. After the war, he returned to Berlin briefly to screen technical documents for the military.
He earned his doctorate in chemistry at Illinois in 1948 and, after several postdoctoral positions, spent his entire career at Berkeley.
His first wife, the former Ingrid Loftsdottir, died in 1993.
Stent is survived by his second wife, Mary Ulam; a son, Stefan Stent of Washington, D.C.; and two stepsons, Alexander Ulam and Joseph Ulam.