Corrigendum: Molecular analysis of the UV-inducible pili operon from Sulfolobus acidocaldarius (vol 2, pg 928, 2013)

Correction regarding Sulfolobus acidocaldarius strain GA06 Upon resequencing we discovered that strain GA06 was not, as published (van Wolferen et al., 2013), a deletion of the upsX ORF and a 40 bp upstream region, but was a deletion starting 55 bp upstream and ending 35 bp downstream of upsX. Since this could affect the genes downstream of UpsX, a clean deletion mutant of the upsX promoter (all 261 bp upstream of upsX) was created and analysed by qRT-PCR studies as well as by UV-induced aggregation assays. qRT-PCR experiments showed that in this strain, upsE, F, A and B were upregulated normally upon UV-induction, and aggregation experiments showed that the deletion mutant of the upsX promoter aggregated in a similar manner as the WT strain after treatment with UV-light. These results are similar to the results obtained for the deletion of the upsX gene (MW115, ΔupsX, Figures 4 and 5). Therefore, the promoter in front of upsX is not the primary promoter of the ups-operon and is also not essential for transcription of the other ups-genes. Additionally, we discovered that the EM image in Figure 6 (GA06) was accidently replaced by an image of strain (ΔupsEF). Both strains did not show any UV induced pili, but the specific image shown was not obtained for this strain. All other strains and EM pictures and the conclusions obtained with these strains are correct

Patterns of Gene Flow Define Species of Thermophilic Archaea

A genomic view of speciation in Archaea shows higher rates of gene flow within coexisting microbial species than between them

Expanding and understanding the genetic toolbox of the hyperthermophilic genus Sulfolobus

Although Sulfolobus species are among the best studied archaeal micro-organisms, the development and availability of genetic tools has lagged behind. In the present paper, we discuss the latest progress in understanding recombination events of exogenous DNA into the chromosomes of Sulfolobus solfataricus and Sulfolobus acidocaldarius and their application in the construction of targeted-deletion mutant strains

UV-inducible DNA exchange in hyperthermophilic archaea mediated by type IV pili

Archaea, like bacteria and eukaryotes, contain proteins involved in various mechanisms of DNA repair, highlighting the importance of these processes for all forms of life. Species of the order Sulfolobales of hyperthermophilic crenarchaeota are equipped with a strongly UV-inducible type IV pilus system that promotes cellular aggregation. Here we demonstrate by fluorescence in situ hybridization that cellular aggregates are formed based on a species-specific recognition process and that UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency. Recombination rates exceeded those of uninduced cultures by up to three orders of magnitude. Knockout strains of Sulfolobus acidocaldarius incapable of pilus production could not self-aggregate, but were partners in mating experiments with wild-type strains indicating that one cellular partner can mediate the DNA transfer. Since pilus knockout strains showed decreased survival upon UV treatment, we conclude that the UV-inducible DNA transfer process and subsequent homologous recombination represents an important mechanism to maintain chromosome integrity in Sulfolobus. It might also contribute substantially to the frequent chromosomal DNA exchange and horizontal gene transfer in these archaea in their natural habitat.

Reducing Time to Antibiotic Administration for Febrile Neutropenia in the Emergency Department

Purpose: Febrile neutropenia (FN) is an oncologic emergency, and prolonged time to antibiotic administration (TTA) is associated with increased hospital length of stay (LOS) and worse outcomes. We hypothesized that a febrile neutropenia pathway (FNP) quality initiative project would reduce TTA delays for febrile patients with cancer presenting to the emergency department (ED). Methods: This prospective study compared ED FNP patients (> 18 years old), between June 2012 and June 2013 with both historical and direct admissions (DA) cohorts at a multispecialty academic center. Interventions included providing patients with FN-Alert cards, standardizing the definition of FN and recognizing it as a distinct chief complaint, revising ED triage level for FN, creating electronic FN order sets, administering empiric antibiotics before neutrophil count result, and relocating FN antibiotics to the ED. The primary outcome was TTA, with a target goal of 90 minutes after ED presentation. Results: In total, 276 FN episodes in 223 FNP patients occurred over the 12-month study period and were compared with 107 episodes in 87 patients and 114 episodes in 101 patients in the historical and DA cohorts, respectively. Use of the FNP reduced TTA from 235 and 169 minutes in historical and DA cohorts, respectively, to 81 minutes, and from 96 to 68 minutes when the order set was not used versus used in the FNP group (P < .001 for all comparisons). Decrease in hospital LOS was not statistically significant. Conclusion: The ED FNP is a significant quality initiative with sustainable interventions, and was able to demonstrate value by decreasing TTA compared to both historical and DA controls in cancer patients presenting to the ED