Suppression of water-bloom cyanobacterium Microcystis aeruginosa by algaecide hydrogen peroxide maximized through programmed cell death

2020 ◽  
Vol 393 ◽  
pp. 122394 ◽  
Author(s):  
Tingru Zhou ◽  
Huansheng Cao ◽  
Jie Zheng ◽  
Fei Teng ◽  
Xuejian Wang ◽  
...  
2005 ◽  
Vol 168 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Tsanko S. Gechev ◽  
Jacques Hille

Hydrogen peroxide (H2O2) has established itself as a key player in stress and programmed cell death responses, but little is known about the signaling pathways leading from H2O2 to programmed cell death in plants. Recently, identification of key regulatory mutants and near-full genome coverage microarray analysis of H2O2-induced cell death have begun to unravel the complexity of the H2O2 network. This review also describes a novel link between H2O2 and sphingolipids, two signals that can interplay and regulate plant cell death.


2008 ◽  
Vol 9 (4) ◽  
pp. 435-445 ◽  
Author(s):  
OLIVIA J. DESMOND ◽  
JOHN M. MANNERS ◽  
AMBER E. STEPHENS ◽  
DONALD J. MACLEAN ◽  
PEER M. SCHENK ◽  
...  

2015 ◽  
Vol 42 (4) ◽  
pp. 337 ◽  
Author(s):  
Juan Liu ◽  
Yanhong Xu ◽  
Zheng Zhang ◽  
Jianhe Wei

Aquilaria sinensis (Lour.) Gilg produces a highly valuable agarwood characterised by a diverse array of sesquiterpenes and chromone derivatives that can protect wounded trees against potential herbivores and pathogens. A defensive reaction on the part of the plant has been proposed as the key reason for agarwood formation, but the issue of whether programmed cell death (PCD), an important process of plant immune responding, is involved in agarwood formation, still needs to be clarified. In this study, treatment of cultured cell suspensions with hydrogen peroxide (H2O2) induced the production of sesquiterpenes due to endogenous accumulation of salicylic acid (SA) and elevations in the expression of sesquiterpene biosynthetic genes. Moreover, PCD was stimulated by H2O2 in cultured cell suspensions of A. sinensis due to the induction of caspase activity, upregulated expression of metacaspases and cytochrome c, and SA accumulation. Our findings demonstrate for the first time that H2O2 stimulates PCD, SA accumulation and sesquiterpene production in cultured cell suspensions of A. sinensis. Furthermore, results from this study provide a valuable insight into investigations of the potential interactions between sesquiterpene synthesis and PCD during agarwood formation.


2007 ◽  
Vol 6 (10) ◽  
pp. 1745-1757 ◽  
Author(s):  
Nancy Lee ◽  
Sreenivas Gannavaram ◽  
Angamuthu Selvapandiyan ◽  
Alain Debrabant

ABSTRACT In this report, we have characterized two metacaspases of Leishmania donovani, L. donovani metacaspase-1 (LdMC1) and LdMC2. These two proteins show 98% homology with each other, and both contain a characteristic C-terminal proline-rich domain. Both genes are transcribed in promastigotes and axenic amastigotes of L. donovani; however, LdMC1 shows increased mRNA levels in axenic amastigotes. An anti-LdMC antibody was obtained and showed reactivity with a single ∼42-kDa protein band in both promastigote and axenic amastigote parasite whole-cell lysates by Western blotting. Pulse-chase experiments suggest that LdMCs are not synthesized as proenzymes, and immunofluorescence studies show that LdMCs are associated with the acidocalcisome compartments of L. donovani. Enzymatic assays of immunoprecipitated LdMCs show that native LdMCs efficiently cleave trypsin substrates and are unable to cleave caspase-specific substrates. Consistently, LdMC activity is insensitive to caspase inhibitors and is efficiently inhibited by trypsin inhibitors, such as leupeptin, antipain, and N α-tosyl-l-lysine-chloromethyl ketone (TLCK). In addition, our results show that LdMC activity was induced in parasites treated with hydrogen peroxide, a known trigger of programmed cell death (PCD) in Leishmania and that parasites overexpressing metacaspases are more sensitive to hydrogen peroxide-induced PCD. These findings suggest that Leishmania metacaspases are not responsible for the caspase-like activities reported in this organism and suggest a possible role for LdMCs as effector molecules in Leishmania PCD.


2014 ◽  
Vol 27 (10) ◽  
pp. 1070-1080 ◽  
Author(s):  
Linlin Chen ◽  
Danyu Shen ◽  
Nannan Sun ◽  
Jing Xu ◽  
Wen Wang ◽  
...  

During pathogenic interactions, both the host and pathogen are exposed to conditions that induce programmed cell death (PCD). Certain aspects of PCD have been recently examined in eukaryotic microbes but not in oomycetes. Here, we identified conserved TatD proteins in Phytophthora sojae; the proteins are key components of DNA degradation in apoptosis. We selected PsTatD4 for further investigation because the enzyme is unique to the oomycete branch of the phylogenetic tree. The purified protein exhibited DNase activity in vitro. Its expression was upregulated in sporangia and later infective stages but downregulated in cysts and during early infection. Functional analysis revealed that the gene was required for sporulation and zoospore production, and the expression levels were associated with the numbers of hydrogen-peroxide-induced terminal dUTP nick end-labeling-positive cells. Furthermore, overexpression of PsTatD4 gene reduced the virulence in a susceptible soybean cultivar. Together, these data suggest that apoptosis may play different roles in the early and late infective stages of P. sojae, and that PsTatD4 is a key regulator of infection. The association of PsTatD4 and apoptosis will lay a foundation to understanding the basic biology of apoptosis and its roles in P. sojae disease cycle.


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