@article{BroekerRoskeVallerianietal.2019,
  author    = {Broeker, Nina K. and Roske, Yvette and Valleriani, Angelo and Stephan, Mareike Sophia and Andres, Dorothee and Koetz, Joachim and Heinemann, Udo and Barbirz, Stefanie},
  title     = {Time-resolved DNA release from an O-antigen-specific Salmonella bacteriophage with a contractile tail},
  series = {The journal of biological chemistry},
  volume    = {294},
  journal   = {The journal of biological chemistry},
  number    = {31},
  publisher = {American Society for Biochemistry and Molecular Biology},
  address   = {Bethesda},
  issn      = {1083-351X},
  doi       = {10.1074/jbc.RA119.008133},
  pages     = {11751 -- 11761},
  year      = {2019},
  abstract  = {Myoviruses, bacteriophages with T4-like architecture, must contract their tails prior to DNA release. However, quantitative kinetic data on myovirus particle opening are lacking, although they are promising tools in bacteriophage-based antimicrobial strategies directed against Gram-negative hosts. For the first time, we show time-resolved DNA ejection from a bacteriophage with a contractile tail, the multi-O-antigen-specific Salmonella myovirus Det7. DNA release from Det7 was triggered by lipopolysaccharide (LPS) O-antigen receptors and notably slower than in noncontractile-tailed siphoviruses. Det7 showed two individual kinetic steps for tail contraction and particle opening. Our in vitro studies showed that highly specialized tailspike proteins (TSPs) are necessary to attach the particle to LPS. A P22-like TSP confers specificity for the Salmonella Typhimurium O-antigen. Moreover, crystal structure analysis at 1.63 angstrom resolution confirmed that Det7 recognized the Salmonella Anatum O-antigen via an E15-like TSP, DettilonTSP. DNA ejection triggered by LPS from either host showed similar velocities, so particle opening is thus a process independent of O-antigen composition and the recognizing TSP. In Det7, at permissive temperatures TSPs mediate O-antigen cleavage and couple cell surface binding with DNA ejection, but no irreversible adsorption occurred at low temperatures. This finding was in contrast to short-tailed Salmonella podoviruses, illustrating that tailed phages use common particle-opening mechanisms but have specialized into different infection niches.},
  language  = {en}
}
@misc{BeisnerGrossartGasol2019,
  author    = {Beisner, Beatrix E. and Grossart, Hans-Peter and Gasol, Josep M.},
  title     = {A guide to methods for estimating phago-mixotrophy in nanophytoplankton},
  series = {Journal of plankton research},
  volume    = {41},
  journal   = {Journal of plankton research},
  number    = {2},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0142-7873},
  doi       = {10.1093/plankt/fbz008},
  pages     = {77 -- 89},
  year      = {2019},
  abstract  = {Growing attention to phytoplankton mixotrophy as a trophic strategy has led to significant revisions of traditional pelagic food web models and ecosystem functioning. Although some empirical estimates of mixotrophy do exist, a much broader set of in situ measurements are required to (i) identify which organisms are acting as mixotrophs in real time and to (ii) assess the contribution of their heterotrophy to biogeochemical cycling. Estimates are needed through time and across space to evaluate which environmental conditions or habitats favour mixotrophy: conditions still largely unknown. We review methodologies currently available to plankton ecologists to undertake estimates of plankton mixotrophy, in particular nanophytoplankton phago-mixotrophy. Methods are based largely on fluorescent or isotopic tracers, but also take advantage of genomics to identify phylotypes and function. We also suggest novel methods on the cusp of use for phago-mixotrophy assessment, including single-cell measurements improving our capacity to estimate mixotrophic activity and rates in wild plankton communities down to the single-cell level. Future methods will benefit from advances in nanotechnology, micromanipulation and microscopy combined with stable isotope and genomic methodologies. Improved estimates of mixotrophy will enable more reliable models to predict changes in food web structure and biogeochemical flows in a rapidly changing world.},
  language  = {en}
}