scholarly journals Mapping of the chaperone AcrH binding regions of translocators AopB and AopD and characterization of oligomeric and metastable AcrH-AopB-AopD complexes in the type III secretion system of Aeromonas hydrophila

2009 ◽  
Vol 18 (8) ◽  
pp. 1724-1734 ◽  
Author(s):  
Yih Wan Tan ◽  
Hong Bing Yu ◽  
J. Sivaraman ◽  
Ka Yin Leung ◽  
Yu-Keung Mok
2007 ◽  
Vol 43 (4) ◽  
pp. 147-160 ◽  
Author(s):  
Johanna C. Sierra ◽  
Giovanni Suarez ◽  
Jian Sha ◽  
Sheri M. Foltz ◽  
Vsevolod L. Popov ◽  
...  

2005 ◽  
Vol 73 (10) ◽  
pp. 6446-6457 ◽  
Author(s):  
Jian Sha ◽  
Lakshmi Pillai ◽  
Amin A. Fadl ◽  
Cristi L. Galindo ◽  
Tatiana E. Erova ◽  
...  

ABSTRACT Many gram-negative bacteria use a type III secretion system (TTSS) to deliver effector proteins into host cells. Here we report the characterization of a TTSS chromosomal operon from the diarrheal isolate SSU of Aeromonas hydrophila. We deleted the gene encoding Aeromonas outer membrane protein B (AopB), which is predicted to be involved in the formation of the TTSS translocon, from wild-type (WT) A. hydrophila as well as from a previously characterized cytotoxic enterotoxin gene (act)-minus strain of A. hydrophila, thus generating aopB and act/aopB isogenic mutants. The act gene encodes a type II-secreted cytotoxic enterotoxin (Act) that has hemolytic, cytotoxic, and enterotoxic activities and induces lethality in a mouse model. These isogenic mutants (aopB, act, and act/aopB) were highly attenuated in their ability to induce cytotoxicity in RAW 264.7 murine macrophages and HT-29 human colonic epithelial cells. The act/aopB mutant demonstrated the greatest reduction in cytotoxicity to cultured cells after 4 h of infection, as measured by the release of lactate dehydrogenase enzyme, and was avirulent in mice, with a 90% survival rate compared to that of animals infected with Act and AopB mutants, which caused 50 to 60% of the animals to die at a dose of three 50% lethal doses. In contrast, WT A. hydrophila killed 100% of the mice within 48 h. The effects of these mutations on cytotoxicity could be complemented with the native genes. Our studies further revealed that the production of lactones, which are involved in quorum sensing (QS), was decreased in the act (32%) and aopB (64%) mutants and was minimal (only 8%) in the act/aopB mutant, compared to that of WT A. hydrophila SSU. The effects of act and aopB gene deletions on lactone production could also be complemented with the native genes, indicating specific effects of Act and the TTSS on lactone production. Although recent studies with other bacteria have indicated TTSS regulation by QS, this is the first report describing a correlation between the TTSS and Act of A. hydrophila and the production of lactones.


2009 ◽  
Vol 296 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Yukihiro Akeda ◽  
Kanna Okayama ◽  
Tomomi Kimura ◽  
Rikard Dryselius ◽  
Toshio Kodama ◽  
...  

Burns ◽  
2012 ◽  
Vol 38 (8) ◽  
pp. 1192-1197 ◽  
Author(s):  
Fereshteh Jabalameli ◽  
Akbar Mirsalehian ◽  
Babak Khoramian ◽  
Marzieh Aligholi ◽  
Seyed Sajjad Khoramrooz ◽  
...  

2004 ◽  
Vol 72 (3) ◽  
pp. 1248-1256 ◽  
Author(s):  
H. B. Yu ◽  
P. S. Srinivasa Rao ◽  
H. C. Lee ◽  
S. Vilches ◽  
S. Merino ◽  
...  

ABSTRACT Aeromonas hydrophila is a gram-negative opportunistic pathogen in fish and humans. Many bacterial pathogens of animals and plants have been shown to inject anti-host virulence determinants into the hosts via a type III secretion system (TTSS). Degenerate primers based on lcrD family genes that are present in every known TTSS allowed us to locate the TTSS gene cluster in A. hydrophila AH-1. A series of genome walking steps helped in the identification of 25 open reading frames that encode proteins homologous to those in TTSSs in other bacteria. PCR-based analysis showed the presence of lcrD homologs (ascV) in all of the 33 strains of A. hydrophila isolated from various sources. Insertional inactivation of two of the TTSS genes (aopB and aopD) led to decreased cytotoxicity in carp epithelial cells, increased phagocytosis, and reduced virulence in blue gourami. These results show that a TTSS is required for A. hydrophila pathogenesis. This is the first report of sequencing and characterization of TTSS gene clusters from A. hydrophila. The TTSS identified here may help in developing suitable vaccines as well as in further understanding of the pathogenesis of A. hydrophila.


2015 ◽  
Vol 104 (12) ◽  
pp. 4065-4073 ◽  
Author(s):  
Xiaotong Chen ◽  
Shyamal P. Choudhari ◽  
Prashant Kumar ◽  
Ronald T. Toth ◽  
Jae Hyun Kim ◽  
...  

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