Polystyrene colonization.

<p><b>Panel A.</b> Representative images of <i>A. baumannii</i> strains ATCC17978 and 98-37-09 colonization of 24 well polystyrene microtiter plates as visualized by crystal violet staining after 48 h incubation at 37°C. <b>Panel B.</b> Representative images of <i>A. baumannii</i> strains ATCC17978, ACJ7, and 98-37-09 colonization of polystyrene tubes after 48 h incubation.</p

Genes down-regulated in RNase T2 mutant cells.

1<p>ATCC17978 locus tag; adjacent loci are highlighted in grey; loci associated with pili formation and motility are bolded.</p

Motility of <i>A. baumannii</i> strains.

<p><b>Panel A.</b> Images displaying the motility properties of <i>A. baumannii</i> strains 98-37-09, 98-37-09 (pWH1266; vector), ACJ7, ACJ7 (pWH1266), and ACJ7 (pACJ02; RNase T2 complementation plasmid). <b>Panel B.</b> For each strain, the diameter across the largest portion of the resulting cell motility halo was measured in millimeters, averaged (n = 3) and plotted; the Wilcoxon rank sum test (NS: not significant, i.e. <i>p</i>≥0.05, or significant at <i>p</i><0.05) are shown above each pair of strain-specific data.</p

Bacterial strains and plasmids used in this study.

1<p>Ampicillin (Amp); Kanamycin (Kan); Tetracycline (Tet), Resistant (r).</p>2<p>American Type Culture Collection (ATCC).</p

Surface colonization properties of <i>A. baumannii</i> strains.

<p>Shown are images and corresponding quantified measures of solubilized crystal violet stained <i>A. baumannii</i> wildtype, ACJ7, and RNase T2 family complemented cells to polypropylene endotracheal tubes at 37°C (<b>Panels A</b> and <b>B</b>; n = 3/group), glass cover slips (25°C; <b>Panels C</b> and <b>D</b>; n = 3/group), and stainless steel disks (25°C; <b>Panels E</b> and <b>F</b>; and 37°C; <b>Panels G</b> and <b>H</b>; n = 5/group for these disks). Asterisks indicate statistically significant differences between wildtype, ACJ7, and complement strain adherence as determined by two-way Analysis of Variance (<i>p</i><0.05). Each data set is representative of at least two independent experiments.</p

Distinct Sources of Hematopoietic Progenitors Emerge before HSCs and Provide Functional Blood Cells in the Mammalian Embryo

Hematopoietic potential arises in mammalian embryos before adult-repopulating hematopoietic stem cells (HSCs). At embryonic day 9.5 (E9.5), we show the first murine definitive erythro-myeloid progenitors (EMPs) have an immunophenotype distinct from primitive hematopoietic progenitors, maturing megakaryocytes and macrophages, and rare B cell potential. EMPs emerge in the yolk sac with erythroid and broad myeloid, but not lymphoid, potential. EMPs migrate to the fetal liver and rapidly differentiate, including production of circulating neutrophils by E11.5. Although the surface markers, transcription factors, and lineage potential associated with EMPs overlap with those found in adult definitive hematopoiesis, they are present in unique combinations or proportions that result in a specialized definitive embryonic progenitor. Furthermore, we find that embryonic stem cell (ESC)-derived hematopoiesis recapitulates early yolk sac hematopoiesis, including primitive, EMP, and rare B cell potential. EMPs do not have long-term potential when transplanted in immunocompromised adults, but they can provide transient adult-like RBC reconstitution