Transmission electron micrographs showing morphology of <i>B. bacilliformis</i>.

<p>Bacteria were grown three days on heart infusion agar containing 4% sheep erythrocytes and 2% sheep serum at 30°C and 100% relative humidity. Cells were subsequently fixed in 2% glutaraldehyde in cacodylate (pH 7.2), epoxy embedded by standard methods, then sectioned and stained with uranyl acetate (UA) and lead citrate stains. Micrographs show <i>B. bacilliformis</i> (strain KC583): (A) from a thin section; (B) applied directly to a grid stained with UA to show flagella. Scale bars represent 100 nm in (A) and 500 nm in (B).</p

Clinical manifestations of Carrión's disease.

<p>(A) Erythrocyte infection during OF, as observed in a blood smear stained with Wright's stain (reprinted by permission from <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002919#pntd.0002919-Hodgson1" target="_blank">[203]</a>). (B) VP lesions on a child in Peru (reproduced from Future Microbiology 4(6): 743–758 (2009) with permission of Future Medicine, Ltd).</p

<i>B. bacilliformis</i> infection of a phlebotomine sand fly.

<p>(A) Female <i>L. verrucarum</i> at 16 h post-feeding with an artificial blood feeder containing human blood and GFP-expressing <i>B. bacilliformis</i> (low-passage strains 14866 and 14868). (B) Light micrograph of <i>L. verrucarum</i> midgut at five days post-feeding on human blood containing GFP⁺<i>B. bacilliformis</i>. Central brown area is residual blood meal. (C) Corresponding UV light micrograph of (B). Note the GFP⁺<i>B. bacilliformis</i> in residual blood meal and elsewhere in the midgut.</p

Scanning electron micrographs of deformin-induced invaginations and pits on erythrocyte membranes.

<p><i>B. bacilliformis</i> colonization of cell membrane deformations is readily apparent. Reprinted by permission from <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002919#pntd.0002919-Benson1" target="_blank">[34]</a>.</p

Genomic structure of seven <i>Bartonella</i> chromosomes.

<p>(A) Chromosomes (Chr) are arranged in size from largest (<i>B. tribocorum</i>) to smallest (<i>B. bacilliformis</i>). Plasmid (Pla) sizes are listed, if present. <i>B. quintana</i>'s genome encodes the least number of proteins (1,142), and <i>B. clarridgeiae</i> has the lowest GC% (35.7%). Several virulence-related ORFs have been used to infer phylogeny (<i>fla – vbh</i>) and black circles indicate their presence in a particular species. (B) Multiple alignment of seven complete genomes using pM. Location, orientation and position of <u>l</u>ocally <u>c</u>ollinear syntenic <u>b</u>locks (LCBs) shared amongst all chromosomes are color-coded and connected by lines. User can analyze location, orientation, and size of LCBs in multiple chromosomes simultaneously (red arrowheads). Local rearrangements, duplications, and inversions are easily identified. Abbreviations correspond to the <i>Bartonella</i> species shown in (A).</p

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu