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WASHINGTON, Aug. 4 (Xinhua) -- Researchers have found a way to turn mouse embryonic stem cells into sperm and this finding opens up new avenues for infertility research and treatment, according to a study published Thursday in the online edition of journal Cell,A Kyoto University team coaxed mouse embryonic stem cells into sperm precursors, called primordial germ cells (PGCs), and shown that these cells can give rise to healthy sperm. The researchers say that such in vitro reconstitution of germ cell development represents one of the most fundamental challenges in biology.When transplanted into mice that were unable to produce sperm normally, the stem cell derived PGCs produced normal-looking sperm, which were then used to successfully fertilize eggs. These fertilized eggs, when transplanted into a recipient mother, produced healthy offspring that grew into fertile male and female adult mice. The same procedure could produce fertile offspring from induced pluripotent stem cells that are often derived from adult skin cells."Continued investigations aimed at in vitro reconstitution of germ cell development, including the induction of female primordial germ cell-like cells and their descendants, will be crucial for a more comprehensive understanding of germ cell biology in general, as well as for the advancement of reproductive technology and medicine," the researchers wrote.

BEIJING, July 22 (Xinhuanet) -- Regulation is needed to govern rapidly expanding research in animals containing human tissue or genes, according to the Britain's Academy of Medical Sciences.Using animals with limited humanized traits is not new. Genetically engineered mice containing human DNA are already a mainstay of research into new drugs for diseases like cancer.For instance, Chinese scientists have already introduced human stem cells into goat fetuses and U.S. researchers have studied the idea of creating a mouse with human brain cells.But Martin Bobrow, a professor of medical genetics at the University of Cambridge, who led the Academy's working group, said there were three areas of particular concern."Where people begin to worry is when you get to the brain, to the germ cells, and to the sort of central features that help us recognize what is a person, like skin texture, facial shape and speech," he said.His report recommends that government should put in place a national expert body, working within the existing system for regulating animal research, to oversee such sensitive areas.British ministers said they welcomed the report and would consider its recommendations carefully.

WASHINGTON, Aug. 11 (Xinhua) -- The unique fossils of an adult plesiosaur and its unborn baby may provide the first evidence that these ancient animals gave live birth like mammals, according to a new study to be published Friday in the journal Science.The 78-million-year-old, 15.4-foot-long (4.7-meter-long) adult specimen is a Polycotylus latippinus, one of the giant, carnivorous, four-flippered reptiles that lived during the Mesozoic Era.Dr. Robin O'Keefe of Marshall University in West Virginia and Dr. Luis Chiappe, Dinosaur Institute director of the Natural History Museum in Los Angeles County, have determined that it is the fossil of an embryonic marine reptile contained within the fossil of its mother.The embryonic skeleton contained within shows much of the developing body, including ribs, 20 vertebrae, shoulders, hips, and paddle bones.O'Keefe and Chiappe have also determined that plesiosaurs were unique among aquatic reptiles in giving birth to a single, large offspring, and that they may have lived in social groups and engaged in parental care.Although live birth has been documented in several other groups of Mesozoic aquatic reptiles, no previous evidence of it has been found in the important order of plesiosaurs."Scientists have long known that the bodies of plesiosaurs were not well suited to climbing onto land and laying eggs in a nest," O'Keefe said."So the lack of evidence of live birth in plesiosaurs has been puzzling. This fossil documents live birth in plesiosaurs for the first time, and so finally resolves this mystery."

CHENGDU, Sept. 20 (Xinhua) -- A United Nations official said Tuesday that she hopes China will take every opportunity to reinforce, support and lead the UN's agenda and "infuse it with strength and wisdom.""The more China gives, the better the UN can become," said Renata Lok-Dessallien, UN Resident Coordinator and United Nations Development Program (UNDP) Resident Representative in China, at the Seminar in Memory of the 40th Anniversary of the Resumption of Lawful Rights of China in the United Nations.The three-day seminar from Sept. 19 to 21 is being held in the city of Chengdu in southwest China's Sichuan Province. About 100 UN and Chinese officials are gathering to discuss China's role in the UN, as well as the UN's role in global diplomacy.Lok-Dessallien said that the General Assembly Resolution of Oct. 25, 1971 was an "important milestone in China's international relations and in the history of the United Nations.""It restored the rights of the People's Republic of China in the United Nations and marked China's entry to the world stage," she said.Steven Sabey, a senior policy advisor from the UNDP's China office, said that China plays an important role in facilitating cooperation about the member states of the United Nations."China needs the United Nations, and the United Nations also needs China," said Wu Hailong, China's assistant minister of foreign affairs."We must recognize that as the largest developing country in the world, China needs to manage its domestic affairs first, as this can have a positive effect on humanity as a whole," Wu said.As China's role in the world continues to grow and evolve, the UN's role in China will also grow, according to Lok-Dessallien."As China's development trajectory continues to evolve, we are entering significantly new territory in the UN-China relationship," she said.Sabey said that he hopes China will strengthen its cooperation with the United Nations in order to further improve intercultural communication and allow China to contribute more to other developing countries."The United Nations is committed to continuing to deepen and strengthen our partnership as we tackle the many global challenges ahead," said Lok-Dessallien.

SAN FRANCISCO, Sept. 12 (Xinhua) -- Amazon.com Inc. is talking with book publishers to launch a rental subscription service for digital books, U.S. media reported on Monday.Several publishing executives said they aren't enthusiastic about the idea because it could lower the value of books and it could also strain their relationships with other retailers that sell their books, The Wall Street Journal quotes people familiar with the matter in a report.The Seattle-based company is considering a digital book library featuring old titles, which would be available to Amazon Prime subscribers, who currently pay 79 U.S. dollars a year for access to digital library of movies and TV shows and unlimited two-day shipping, said the report.Amazon would offer book publishers a substantial fee and could limit the amount of books that Amazon Prime customers could read for free every month, the report cited some sources as saying.The online retailing giant makes the popular electronic reader Kindle and is also reported to launch a color touchscreen tablet before October to compete with Apple's iPad and other devices in the increasingly crowded tablet computer market.The proposal is another sign that retailers are looking for more ways to deliver content digitally as customers increasingly read book and watch TV on personal computers, tablets and other electronic devices, said The Wall Street Journal report.