Radzisheuskaya a & Silver JCR (2014) do all roads lead to oct4?  the emerging concepts of induced pluripotency. Trends Cell Biol. 24, 275–284.
Sasai y, eiraku m & Suga h (2012) In vitro organogenesis in three dimensions: self-organising stem cells. Development 139, 4111–4121.
Soza-Ried J & Fisher aG (2012) Reprogramming somatic cells towards pluripotency by cellular fusion. Curr. Opin. Genet. Dev. 22, 459–465.
takahashi k & yamanaka S (2006) induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 126, 663–676.
theunissen tw & Jaenisch R (2014) molecular control of induced pluripotency. Cell Stem Cell 14, 720–734.
watanabe a, yamada y & yamanaka S (2013) epigenetic regulation in pluripotent stem cells: a key to breaking the epigenetic barrier. Philos. Trans. R. Soc. Lond. B Biol. Sci. 368, 20120292.
yamanaka S (2013) the winding road to pluripotency (nobel lecture). Angew. Chem. Int. Ed. Engl. 52, 13900–13909.
Infectious diseases currently cause about one-quarter of all human deaths worldwide, more than all forms of cancer combined and second only to cardiovascular diseases. In addition to the continuing heavy burden of ancient diseases such as tuberculosis and malaria, newer infectious diseases continually emerge. The current pandemic (worldwide epidemic) of AIDS (acquired immune deficiency syndrome), was first clinically observed in 1981 and has since caused more than 35 million deaths worldwide. Moreover, some diseases long thought to result from other causes are now recognized to be associated with infections. Most gastric ulcers, for example, are caused not by stress or spicy food, but by infection of the stomach lining by the bacterium Helicobacter pylori.
The burden of infectious diseases is not spread equally across the planet. Poorer countries and communities suffer disproportionately, often due to poor public sanitation and health systems. Some infectious diseases, however, occur primarily or exclusively in industrialized communities: Legionnaire’s disease, for example, a bacterial infection of the lungs, commonly spreads through air-conditioning systems.
Since the mid-1800s, physicians and scientists have struggled to identify the agents—collectively called pathogens—that are capable of causing infectious diseases. More recently, the advent of microbial genetics and molecular cell biology has greatly enhanced our understanding of the causes and mechanisms of infectious diseases. We now know that pathogens frequently exploit the attributes of their host’s cells in order to infect them. This understanding can give us new insights into normal cell biology, as well as strategies for treating and preventing infectious diseases.
Although pathogens are understandably a focus of attention, only a relatively small fraction of the microbial species we encounter are pathogens. Much of the biomass of the Earth is made up of microbes, and they produce everything from the oxygen we breathe to the soil nutrients we use to grow food. Even those species of microbes that colonize the human body do not generally cause disease. The collective of microorganisms that reside in or on an organism is called the microbiota. Many of these microbes have a beneficial effect on the health of the organism, assisting its normal development and physiology.