Abstract Programmed cell death (PCD) is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20%) of the total cell population, depending on the cell type and host developmental stage. The Hunter Crack Offline Bible on this page.

Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays), together with visualization of cytoskeleton alterations (FITC-phalloidin staining), showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20) further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom. Citation: Zheng W, Rasmussen U, Zheng S, Bao X, Chen B, Gao Y, et al.

(2013) Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial) Endosymbiont. PLoS ONE 8(6): e66147. Editor: Nicolas Fasel, University of Lausanne, Switzerland Received: December 19, 2012; Accepted: May 2, 2013; Published: June 18, 2013 Copyright: © 2013 Zheng et al.

Thanks for the video, but I would like to ask a question. One of the text books that I read said that the difference. Eukaryotic Cell (EC) publishes reports of basic research on eukaryotic microorganisms such as yeasts, fungi, algae, protozoa, and social amoebae. Topics include but. Studies that only catalog differences and similarities between genotypes or responses to stimuli are not likely to be reviewed favorably. In addition, EC will. And virulence of pathogens are strain dependent and vary greatly between members of the same species. Thus, the prokaryotic species includes organisms that are func- tionally as well as genetically different, and should there- fore be compared with some deeper eukaryotic classification level such as the.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The financial support from the Swedish Research Council Formas and the Swedish Energy Agency (to B.B.), the Swedish Research Council Link program (to U.R.

And W.W.Z.), the National Natural Science Foundation of China (Grant 31071745 to X.G. And W.W.Z.), and the Science and Technology Foundation of Fujian Province, China (Grant 2010R1021-8; to S.P.Z.) is gratefully acknowledged. The authors also thank K. Wallenberg Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Introduction Programmed cell death (PCD) is a self-inflicted genetically-based cell death mechanism in eukaryotic organisms, and genetic and cytological studies have led to the identification of pathways and molecular components that underlie this process –.

Emerging evidence suggests that PCD may also be operative in prokaryotes, which were previously considered to be immortal unless killed or eaten by predators. PCD may for instance be involved in developmental life cycles and in optimizing adaptations in natural prokaryotic populations subjected to environmental stresses –. Mechanisms that balance life and death are also known to protect against antibiotics and macrophages during bacterial biofilm formation. Studies of prokaryotic PCD have primarily focused on autolysis and in a limited number of bacteria, such as Echerichia coli –.