H high inclusion rate of consecutive patients, thus providing high external validity. All available samples were screened for influenza which provides detailed information regarding the impact of the epidemic. However, it has limitations. Despite including 94 of available patients the number of cases is low. It is possible that the proportion of CAP attributable to influenza may be underrated due to false negative test results from PCR of nasopharyngeal swabs. However, no increase in undiagnosed or bacterial 1676428 pneumonia was noted during the epidemic period suggesting that this should was not a major problem. Broncho-alveolar lavage may be more sensitive in the diagnosis of influenza pneumonia [35], but subjecting all admitted patients with CAP to bronchoscopy is not ethically acceptable. Furthermore, occasional patients may have been admitted to smaller hospitals. This is unlikely to make an impact in our results however, since our hospitals hold 70 of all hospital beds in the country. In summary, patients with pneumonia due to influenza A 2009 (H1N1) were younger than other patients with CAP, and required intensive care and mechanical ventilation more frequently. Despite having a more severe disease, they had lower PSI and CURB-65 scores on admission, suggesting that modification of these prediction rules may be warranted in the setting of novel pathogens to which the herd immunity is low. Last, but not least these results remind us of the importance of clinical acumen in decision making.Supporting InformationFigure S1 Total number 16574785 of patients admitted with communityacquired pneumonia (CAP) and influenza CAP, by study quarters. (TIF)AcknowledgmentsThe authors wish to thank Ingibjorg Richter for providing hospital data on 94-09-7 site admissions as well as the house staff, nurses, and laboratory personnel of Landspitali University Hospital for their assistance in recruiting participants and collecting and preserving samples. We thank Mark A. Miller for critical review and helpful comments on the manuscript.Author ContributionsConceived and designed the experiments: AB HA OB KGK MG. LED-209 chemical information Performed the experiments: AB JFG HA KLH BSK. 
Analyzed the data: AB GT AL GH MG. Contributed reagents/materials/analysis tools: GT AL GH KGK. Wrote the paper: AB GT AL JFG HA KLH BSK OB GH KGK MG.
Germ layer formation is one of the most important processes in the fundamental patterning of an embryo. In Xenopus early embryogenesis, mesoderm is induced by signals secreted from endodermal tissue during the blastula stage, and nodal-related (Xnr) genes are known to play important roles in this biological process. VegT and Wnt signaling induces ��nr5/6, followed by the sequential upregulation of Xnr1/2 and Xnr4 [1?], and consequently, various mesoderm gene activities. Activin A, a TGF-?superfamily member, was first identified as a factor that could induce both ventral and dorsal mesoderm [4]. In dorsal mesoderm, also called the SpemannMangold organizer, several genes including chordin (chd), noggin (nog), goosecoid (gsc), and xlim-1 are expressed to induce neural tissues in the presumptive neuroectoderm [5?]. Xenopus blastula ectodermal cells, or animal cap (AC) cells, possess multipotency and can differentiate into many types of tissues including mesoderm. However, the period for mesoderm induction in AC is limited until early gastrula. This phenomenon is known as “loss of mesodermal competence” (LMC) [9]. To identify novel factors involved with maintaining multipotency in Xe.H high inclusion rate of consecutive patients, thus providing high external validity. All available samples were screened for influenza which provides detailed information regarding the impact of the epidemic. However, it has limitations. Despite including 94 of available patients the number of cases is low. It is possible that the proportion of CAP attributable to influenza may be underrated due to false negative test results from PCR of nasopharyngeal swabs. However, no increase in undiagnosed or bacterial 1676428 pneumonia was noted during the epidemic period suggesting that this should was not a major problem. Broncho-alveolar lavage may be more sensitive in the diagnosis of influenza pneumonia [35], but subjecting all admitted patients with CAP to bronchoscopy is not ethically acceptable. Furthermore, occasional patients may have been admitted to smaller hospitals. This is unlikely to make an impact in our results however, since our hospitals hold 70 of all hospital beds in the country. In summary, patients with pneumonia due to influenza A 2009 (H1N1) were younger than other patients with CAP, and required intensive care and mechanical ventilation more frequently. Despite having a more severe disease, they had lower PSI and CURB-65 scores on admission, suggesting that modification of these prediction rules may be warranted in the setting of novel pathogens to which the herd immunity is low. Last, but not least these results remind us of the importance of clinical acumen in decision making.Supporting InformationFigure S1 Total number 16574785 of patients admitted with communityacquired pneumonia (CAP) and influenza CAP, by study quarters. (TIF)AcknowledgmentsThe authors wish to thank Ingibjorg Richter for providing hospital data on admissions as well as the house staff, nurses, and laboratory personnel of Landspitali University Hospital for their assistance in recruiting participants and collecting and preserving samples. We thank Mark A. Miller for critical review and helpful comments on the manuscript.Author ContributionsConceived and designed the experiments: 
AB HA OB KGK MG. Performed the experiments: AB JFG HA KLH BSK. Analyzed the data: AB GT AL GH MG. Contributed reagents/materials/analysis tools: GT AL GH KGK. Wrote the paper: AB GT AL JFG HA KLH BSK OB GH KGK MG.
Germ layer formation is one of the most important processes in the fundamental patterning of an embryo. In Xenopus early embryogenesis, mesoderm is induced by signals secreted from endodermal tissue during the blastula stage, and nodal-related (Xnr) genes are known to play important roles in this biological process. VegT and Wnt signaling induces ��nr5/6, followed by the sequential upregulation of Xnr1/2 and Xnr4 [1?], and consequently, various mesoderm gene activities. Activin A, a TGF-?superfamily member, was first identified as a factor that could induce both ventral and dorsal mesoderm [4]. In dorsal mesoderm, also called the SpemannMangold organizer, several genes including chordin (chd), noggin (nog), goosecoid (gsc), and xlim-1 are expressed to induce neural tissues in the presumptive neuroectoderm [5?]. Xenopus blastula ectodermal cells, or animal cap (AC) cells, possess multipotency and can differentiate into many types of tissues including mesoderm. However, the period for mesoderm induction in AC is limited until early gastrula. This phenomenon is known as “loss of mesodermal competence” (LMC) [9]. To identify novel factors involved with maintaining multipotency in Xe.
