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dictyNews Volume 42 Number 07
dictyNews
Electronic Edition
Volume 42, number 7
March 4, 2016
Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to dicty@northwestern.edu
or by using the form at
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.
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Abstracts
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Lysosomes appear as the auto-fluorescent vacuoles in Dictyostelium
discoideum cells
Hiroki Kainuma*, Yuya Saito*, Ikuo Hatakeyama, Takako A. Omata and
Saburo Uchiyama**
HK, IH, SU: Laboratory of Biology, Course of Science Education,
Graduate School of Education, Iwate University, Ueda 3-18-33,
Morioka 020-8550, Japan
YS:Laboratory of Biology, Division of Science Education,Faculty of
Education, Iwate University, Morioka, Japan
TAO: Clinical Laboratory, University Hospital, Dokkyo Medical
University, Mibu, Tochigi, Japan
Pteridines, accepted
Dictyostelium discoideum cells contain autofluorescent
vacuoles. To determine the identity of these vacuoles, t
he fluorescent dye 4-nitro-7-(1-piperazinyl)-2,1,3-
benzoxadiazole (NBD-PZ) was used to stain the lysosomes
in D. discoideum cells. Neither the auto-fluorescent
vacuoles nor lysosomes were observed in D. discoideum
cells immediately after they arose from spores or in
stationary phase cells. However, both the auto-fluorescent
vacuoles and lysosomes were visible in cells that had
entered growth phase. Auto-fluorescent vacuoles and
lysosomes were also observed in stationary phase cells
incubated with chloroquine. When the cells were allowed
to phagocytose BioParticles Fluorescent Bacteria (orange
fluorescence) for 1 h, orange phagosomes and blue auto-
fluorescent vacuoles were observed as independent moieties.
However, after an additional 2 h of incubation, we
observed vacuoles with mixed fluorescence (orange and
blue) in the cells, suggestive of secondary lysosomes.
These results suggest that the auto-fluorescent vacuoles
in D. discoideum cells are lysosomes.
submitted by: Saburo Uchiyama [uchiyama@iwate-u.ac.jp]
———————————————————————————————————————
Social amoebae trap and kill bacteria by casting DNA nets
Xuezhi Zhang, Olga Zhuchenko, Adam Kuspa, and Thierry Soldati
Nature Communications, 2016 Mar 1;7:10938. doi: 10.1038/ncomms10938
Extracellular traps (ETs) from neutrophils are reticulated nets of
DNA decorated with antimicrobial granules, and are capable of
trapping and killing extracellular pathogens. Various phagocytes
of mammals and invertebrates produce ETs, however, the evolutionary
history of this DNA-based host defence strategy is unclear. Here
we report for the first time that Sentinel cells of the multicellular
slug stage of the social amoeba Dictyostelium discoideum produce ETs
upon stimulation with bacteria or lipopolysaccharide in a reactive
oxygen species-dependent manner. The production of ETs by Sentinel
cells requires a Toll/Interleukin-1 receptor domain-containing
protein TirA and reactive oxygen species-generating NADPH oxidases.
Disruption of these genes results in decreased clearance of bacterial
infections. Our results demonstrate that D. discoideum is a powerful
model organism to study the evolution and conservation of mechanisms
of cell-intrinsic immunity, and suggest that the origin of DNA-based
ETs as an innate immune defence predates the emergence of metazoans.
submitted by: Thierry Soldati [thierry.soldati@unige.ch]
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[End dictyNews, volume 42, number 7]
