The means of multiple experiments are shown. All experiments were performed 2-4 times, with each experiment containing 4 replicates. Differences between means were determined using Student's t-test. Differences were considered significant if P,0.05. Significant differences are indicated by symbols in the figures where appropriate. Figure S1 Competition between firefly and Gaussia luciferase reporter genome segments. Plasmids encoding firefly (FNP) or Gaussia (GNP) luciferase reporter constructs were transfected alone (Single) or in combination (Co). Luciferase expression was induced by simultaneous co-transfection of polymerase and NP expression plasmids (transfection assay). A) Firefly luciferase activity after transfection of FNP with empty plasmid (pUC18) or FNP together with GNP. B) Gaussia luciferase activity after transfection of GNP with empty plasmid (pUC18) or GNP together with FNP. C) Normalized ratio of firefly to Gaussia luciferase activity (Fluc/Gluc) when FNP and GNP were transfected singly or in combination. (TIF)  Oral health in China – trends and challenges For a long time, oral disease is one of the major problems of the public health for its high prevalence and incidence throughout the world, which is especially true for low-income populations. Since China's economic reform in 1978, great changes have taken place in China. These changes have significant impact on and have been reflected in oral disease trends in China. This paper provides an overview and assessment of the oral health status in China. It focuses on changes in the nation's demographic profile, in the marketplace, the oral disease status and trends. The paper also suggests some possible measures and strategies for bettering oral health in future China. In recent years, chronic noncontagious diseases have become a major health problem in the world. Besides social and environmental factors, the changes in lifestyle worldwide have great effects on the changes in the disease status and trends. Oral disease is one of the major problems of the public health for its high prevalence and incidence, especially in low-income populations. Oral diseases have become one of the major maladies. This paper provides an overview of the oral health status in China, focusing on changes in the nation's demographic profile, the marketplace, and trends of Chinese dentistry. The paper also suggests some related measures and strategies for improving oral health in future China.