Rita Levi Montalcini, the oldest living and the longest-lived Nobel laureate in history, died today at her home in Rome aged 103.

The announcement was given in a statement by Rome's mayor Gianni Alemanno.

"Her death is a great loss for Italy and all of humanity," Alemanno wrote.

Levi Montalcini is mainly remembered for her ground-breaking research on nerve growth factor, which she discovered (jointly with American co-worker Stanley Cohen), in June 1951 in the labs of Washington University in St. Louis.

A protein essential for the growth, maintenance, and survival of sensory and sympathetic neurons (nerve cells) in the peripheral nervous system, NGF was not widely recognized until 1986, when it won Levi Montalcini and Cohen the Nobel Prize in physiology or medicine.

A petite woman, always exquisitely dressed, Levi Montalcini worked until her final day. She used to spend most of her time in a tiny room of her large house. The room was filled with books, scientific documents and an ultra modern pc.

According to media reports, she worked on her research until yesterday at 9pm.

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Her findings have had a significant influence on research exploring several diseases, including cancer, Parkinson's disease and Alzheimer's disease.

"I lost my sight and hearing. At the conferences I can't see clearly the presentations and I can't hear well. But I can say my mental capacity is greater today than when I was 20 since it has been enriched by so many experiences," she wrote in her Facebook page.

As a senator for life, she harshly criticized Mario Monti's government of technocrats for abolishing the peer review mechanism in funding policies to researchers.

"Italy — and quite possibly the world — has never seen a scientist quite like her," the journal Nature wrote on the occasion of her widely celebrated 100th birthday.

Born with her twin sister, Paola, (who died in 2000 at age 91) to a Jewish family in Turin on April 22, 1909, Levi Montalcini went to medical school, despite the objections of her father.

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He worried that her work as a doctor would interfere with her duties of future wife and mother.

"At 20, I realized that I could not possibly adjust to a feminine role as conceived by my father and asked him permission to engage in a professional career," Levi Montalcini wrote in her biography.

"In eight months I filled my gaps in Latin, Greek and mathematics, graduated from high school, and entered medical school in Turin," she added.

She graduated in 1936, but two years later her career was halted by Mussolini's laws banning "inferior races" from academic and professional careers.

Undaunted, Levi Montalcini set up an improvised laboratory in her bedroom during World War II and studied the growth of nerve fibers in chicken embryos.

After fleeing with her family to Florence in 1943, she worked as a nurse and a doctor treating refugees with infectious diseases.

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After the war, she accepted an invitation to study for a semester at Washington University in St. Louis. She remained there, continuing her work on nerve growth factor, for three decades, calling those years "the happiest and most productive" of her life.

Director of the Institute of Cell Biology of the Italian National Council of Research in Rome from 1968 to 1978, she retained her faculty status at Washington University until 1977, when she became professor emeritus. She held dual Italian-U.S. citizenship.

After 1978, she continued her research at the institute in Rome, collecting innumerable awards and acknowledgments from institutions around the world.

Made a senator for life in 2001 for her work in science and for the promotion and defense of civil rights, Levi Montalcini founded the European Brain Research Institute in 2005 at age 96.

"A beacon of life is extinguished with her death," her niece Piera Levi-Montalcini, told the Italian news agency ANSA.

"At least she did not suffer," she added.

The scientist will be buried in Turin next to her sister Paola.

Photo: Rita Levi Montalcini speaking at the international NGF meeting in 2008. Credit: Wikimedia Commons.