BIOGRAPHY OF PROFESSOR ZHEN YAO

    

Professor Zhen YAO, Ph.D., a distinguished cell biologist and a Member of the Chinese Academy of Sciences, Editor-in-Chief of Cell Research, passed away at 9:55 am on November 4^th, 2005 in Shanghai at the age of 90. He is survived by his wife, Jing DING, his son Li Xing YAO, and granddaughter, Qin Yi YAO.

Professor Zhen YAO (formerly T. YAO) was born in Changshu, Jiangsu Province, China, in October 1915. He graduated from the Department of Biology, Zhejiang University in 1937. Professor Shizhang BEI, a well-known experimental biologist and biophysicist, was the Mentor who introduced him to the field of experimental morphology. Professor YAO began his research work in 1940, studying the soma-differentiation of a cell-constant nematode, Cosmocerca sp. Like the Ascaris megalocephala, the nematode maintained an intact genome only in its germ line cells. Part of its chromatin diminished at a subsequent stage of division in all cells, which were predestined to differentiate into various kinds of somatic cells. Interestingly, he discovered that the diminished chromatin in somatic cells was always in the form of heterochromatin. The nature of the biological significance of this novel finding still remains unclear.

Subsequently, Professor YAO focused his interests on the morphological organization problem of hydra, Pelmatohydra oligactis. Through homoplastic transplantation, he demonstrated that the capability to induce the production of a new hydranth was only limited to the cells of the hypostome, generally regarded as the organization center of the hydra. No gradient of induction potency can be observed. However, the transplantation results of the pedal disc and the tissue implants from the middle body region suggested the presence of a physiological gradient relative to the capacity of the pedal differentiation. This work was later recommended by Professor Joseph NEEDHAM for publication in the Journal of Experimental Biology.

In 1946, Professor YAO obtained a British Council Scholarship and became a graduate student of Professor CH WADDINGTON at the Institute of Animal Genetics, Edinburgh University, Scotland. During his study on the cytochemistry of Drosophila development, he systematically analyzed the localization and change of activities of phosphoesterases, especially alkaline phosphoesterase, during embryogenesis and metamorphosis. He found that alkaline phosphatase was not detectable in the first half of embryonic life, but suddenly appeared in the ventral ectoderm, near the future thorax, during, or shortly after, the contraction of the germ band. Subsequently, the enzyme activity spreads to the other parts of the embryo, following a definite pattern. These astute observations led him to the seminal hypothesis that the center of the origin of alkaline phosphatase is the "differentiation center" of the Drosophila embryo. In 1949, he was conferred with the Doctor of Philosophy degree by Edinburgh University.

Professor YAO returned to China in October 1949 and was appointed a Professor at Zhejiang University. When the Institute of Experimental Biology, Chinese Academy of Sciences, was founded in Shanghai in 1950, Professor YAO was appointed as a Research Professor and he served as Deputy Director of the Institute from 1964-1983. He was elected to Membership of the Chinese Academy of Sciences, Division of Biology, in 1980.

Since the mid 1950s, Professor YAO and his colleagues have been engaged in the study of the induction of tumors of thyroid, ovary and mammary glands in rats, by the experimental manipulation of hormone balance. The studies focused on the histogenesis and histochemistry of these tumors. Investigations included the induction of rat liver carcinoma with chemical carcinogens and the establishment of transplantable hepatoma models. Faced with the alarmingly high incidence of hepatoma in China, difficulty with its early diagnosis and its poor prognosis, he organized and directed a project for the early diagnosis of human hepatoma. In ground breaking research undertaken in 1971, Professor YAO's team was the first to suceed in the use of an immuno-diffusion test for AFP (a-fetoprotein) in mass screening to identify cases of early hepatoma, prior to any other positive indicators utilizing the standard diagnostic methods then available. This work greatly promoted the early diagnosis and immediate treatment of sub-clinical hepatomas in China, a world-renowned achievement.

To explore the possible presence of other embryonic antigens in human hepatoma cells, YAO's group later found a novel embryonic membrane-associated antigen, with characteristics differed from those of the known AFP and CEA.

In 1983, Professor YAO successfully organized and sponsored a project for the production of high-specificity monoclonal antibodies against human hepatocellular carcinoma. Using radioactive iodine-labeled antibodies, tumors were successfully imaged in clinical patients. Later, radioactive iodine-conjugated antibodies were successfully used to de-bulk hepatoma tumors, leading to a substantially improved prognosis and occasional cures following definitive surgical resection.

During this period, Professor YAO also participated in a project studying the tumor-host relationship, which paid particular attention to the presence of suppressor macrophages in the host and their in vitro immunomodulation.

In the 1980s, Professor YAO foresaw the biomedical significance of embryonic stem (ES) cells and established a laboratory for mouse embryonic stem cell biology in 1987. He was particularly interested in the controlled induction of differentiation in mouse ES cells. By over-expressing the human TGF-b1 gene, mouse ES cells were induced to differentiate into endothelial cells and capillaries. YAO's team established porcine ES/EG cells for use in xenotransplantation and successfully obtained several porcine embryonic germ cell (EG cell) lines of Chinese mini-pigs in 2002. To understand the nature of totipotent ES cells, YAO's team have cloned some new downstream genes of the key gene, oct-4, facilitating further studies.

Professor Yao dedicated his whole life to `the advancement of science' both in China and abroad and attached great importance to international academic exchanges. In 1979, he headed a delegation of cell biologists from Chinese Academy of Science visited Great Britain and Sweden, and later, with Prof Xinxian GUO, he led a group of cell biology researchers visited France and Switzerland in 1981. These visits of the delegations enabled the on-the-spot-investigation of cell biology research in these countries. During 1983-1986 and 1996-1999, he was the 2^nd and 6^th President of Chinese Society of Cell Biology (CSCB). He also organized several international symposia in Shanghai and made substantial contributions to the establishment of the Asian-Pacific Organization for Cell Biology (APOCB), and was elected the first president in 1988. Being chairman of the 1st Congress of APOCB, he successfully held the first international meeting and symposium for Cell Biology in Shanghai in 1990.

Professor YAO actively took part in editorial works as board member of many academic journals, including: Acta Biologiae Experimentalis Sinica, Chinese Journal of Cancer Research, Shanghai Journal of Immunology, Cell Biology International Report and served as the associate editor of Acta Biologiae Experimentalis Sinica for many years. In 1990, Professor YAO created an international journal, Cell Research, one of the greatest legacies that he left us. He served as the first Editor-in-Chief for more than 15 years. His dedication, experience and rigorous editorial skills contributed Cell Research to be the best life sciences journal in China. Moreover, under his leadership Cell Research is collaborating with the Nature Publishing Group (NPG) as a partner journal, which has fulfilled his ambition to promote the journal throughout the world.

Professor YAO also gave education and training of new researchers a high priority. He is well respected for mentorship by his students. The students he mentored during his professional career of 65 year have spread throughout the world, many of them achieving high academic honors, following in his footsteps to become excellent researchers.

Professor YAO had always been active in academic thinking, and was noted for his meticulous scholarship. He was diligent, dedicated and generous leader within the research community, and was very kind and willing to give his best to others. The fundamental principle that he followed was: "cultivating interest, pursuing the truth, willingness to help others, and contributing to society". His dedication to science will inspire the younger generation to higher achievements. His great scientific achievements and his inspiring scientific spirit will live in our hearts forever.

We deeply mourn the passing of our distinguished and beloved Professor Zhen YAO.