Simultaneous Identification of Bacterial Virulence Genes by Negative Selection

Hensel, Michael; Shea, Jacqueline E.; Gleeson, Colin; Jones, Michael D.; Dalton, Emma; Holden, David W.

doi:10.1126/science.7618105

Cited by 1,125 publications

(1,051 citation statements)

References 19 publications

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“…The similarities between the ssa gene products and their counterparts encoded by SPI1 in Salmonella and genes of other bacteria provide clear evidence that the Salmonella genome encodes two distinct type III secretion systems (Hensel et al, 1995;Shea et al, 1996;Ochman et al, 1996, and this work). Sequence comparisons between components of different type III secretion systems show that, collectively, the ssa gene products are structurally most similar to the Yersinia spp.…”

Section: Discussionmentioning

confidence: 53%

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Functional analysis of ssaJ and the ssaK/U operon, 13 genes encoding components of the type III secretion apparatus of Salmonella Pathogenicity Island 2

Hensel

Shea

Raupach

et al. 1997

Molecular Microbiology

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163

186

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SummaryWe have investigated the structure and transcriptional organization of 13 genes of Salmonella Pathogenicity Island 2 (SPI2) that encode components of the second type III secretion apparatus of Salmonella typhimurium. ssaK, L, M, V, N, O, P, Q, R, S, T, U constitute one operon of 10 kb. ssaJ lies upstream of ssaK and is the terminal gene of another operon. The deduced products of ssaJ, ssaK, ssaV, ssaN, ssaO, ssaQ, ssaR, ssaS, ssaT, and ssaU show greatest similarity to the Yersinia spp. genes yscJ, yscL, lcrD, yscN, yscO, yscQ, yscR, yscS, yscT, and yscU, respectively. The products of the ssaL, ssaM and ssaP genes do not have significant similarity to products of other type III secretion systems, and might be important for the specific function of the SPI2 type III secretion system. Bacterial strains carrying different ssa mutations display minor alterations in terms of serum sensitivity when compared with the wild-type strain, but none are defective in replication within macrophage-like RAW 264.7 cells. However, some of the ssa mutant strains invade HEp2 cells less efficiently and are less cytotoxic to RAW 264.7 macrophages than the wild-type strain. We show that the invasion defect is correlated with a lack of SipC in culture supernatants of these mutant strains.SipC is a product of the SPI1 type III secretion system of S. typhimurium, and is important for epithelial cell invasion. Therefore, mutations in SPI2 can affect the SPI1 secretion system, which raises the possibility of an interaction between the two type III secretion systems.

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Section: Discussionmentioning

confidence: 53%

“…Recently we and others identified a number of genes that encode a second type III secretion system in S. typhimurium (Hensel et al, 1995;Shea et al, 1996;Ochman et al, 1996). These genes are all located on a second pathogenicity island (SPI2) at 30 centisomes on the chromosome.…”

Section: Introductionmentioning

confidence: 99%

Functional analysis of ssaJ and the ssaK/U operon, 13 genes encoding components of the type III secretion apparatus of Salmonella Pathogenicity Island 2

Hensel

Shea

Raupach

et al. 1997

Molecular Microbiology

Self Cite

163

186

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“…Conjugal delivery of transposons may replace transduction in phage-resistant serovars. A sophisticated procedure for the identification of genes involved in bacterial pathogenesis, developed by Hensel and colleagues, can be also applied to the detection of host adaptation genes [233]. The so-called Signature-Tagged Mutagenesis (STM) employs a mini-Tn5 element that contains a variable DNA sequence tag.…”

Section: Recently Developed Molecular Methods With Application To Stumentioning

confidence: 99%

Host adapted serotypes of Salmonella enterica

et al. 2000

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Salmonella constitutes a genus of zoonotic bacteria of worldwide economic and health importance. The current view of salmonella taxonomy assigns the members of this genus to two species: S. enterica and S. bongori. S. enterica itself is divided into six subspecies, enterica, salamae, arizonae, diarizonae, indica, and houtenae, also known as subspecies I, II, IIIa, IIIb, IV, and VI, respectively [1]. Members of Salmonella enterica subspecies enterica are mainly associated with warm-blooded vertebrates and are usually transmitted by ingestion of food or water contaminated by infected faeces. The pathogenicity of most of the distinct serotypes remains undefined, and even within the most common serotypes, many questions remain to be answered regarding the interactions between the organism and the infected host.Salmonellosis manifests itself in three major forms: enteritis, septicaemia, and abortion, each of which may be present singly or in combination, depending on both the serotype and the host involved. Although currently over 2300 serovars of Salmonella are recognized, only about 50 serotypes are isolated in any significant numbers as human or animal pathogens [2, 3] and they all belong to subspecies enterica. Of these, most cause acute gastroenteritis characterized by a short incubation period and a severe systemic disease in man or animals, characterized by septicaemia, fever and/or abortion, and such serotypes are often associated with one or few host species [4–6].It is the intention of this review to present a summary of current knowledge of these host-adapted serotypes of S. enterica. The taxonomic relationships between the serotypes will be discussed together with a comparison of the pathology and pathogenesis of the disease that they cause in their natural host(s). Since much of our knowledge on salmonellosis is based on the results of work on Typhimurium, this serotype will often be used as the baseline in discussion. It is hoped that an appreciation of the differences that exist in the way these serotypes interact with the host will lead to a greater understanding of the complex host–parasite relationship that characterizes salmonella infections.

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“…Traditionally, transposon insertion mutagenesis has been used to identify gene functions in many different bacteria (Glass et al, 2006; Hensel et al, 1995; Jacobs et al, 2003; Mack et al, 1994), including P. putida KT2440 (de Lorenzo & Timmis, 1994; Herrero, Lorenzo, & Timmis, 1990; Molina‐Henares et al, 2010). However, genome wide screening and identification of all genes involved in tolerance has been a limiting factor, which in the last years have been overcome through the use of next generation sequencing (NGS) techniques.…”

Section: Introductionmentioning

confidence: 99%

Genome‐wide identification of tolerance mechanisms toward p‐coumaric acid in Pseudomonas putida

Calero

Jensen

Bojanovič

et al. 2017

Biotech & Bioengineering

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The soil bacterium Pseudomonas putida KT2440 has gained increasing biotechnological interest due to its ability to tolerate different types of stress. Here, the tolerance of P. putida KT2440 toward eleven toxic chemical compounds was investigated. P. putida was found to be significantly more tolerant toward three of the eleven compounds when compared to Escherichia coli. Increased tolerance was for example found toward p‐coumaric acid, an interesting precursor for polymerization with a significant industrial relevance. The tolerance mechanism was therefore investigated using the genome‐wide approach, Tn‐seq. Libraries containing a large number of miniTn5‐Km transposon insertion mutants were grown in the presence and absence of p‐coumaric acid, and the enrichment or depletion of mutants was quantified by high‐throughput sequencing. Several genes, including the ABC transporter Ttg2ABC and the cytochrome c maturation system (ccm), were identified to play an important role in the tolerance toward p‐coumaric acid of this bacterium. Most of the identified genes were involved in membrane stability, suggesting that tolerance toward p‐coumaric acid is related to transport and membrane integrity.

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Simultaneous Identification of Bacterial Virulence Genes by Negative Selection

Cited by 1,125 publications

References 19 publications

Functional analysis of ssaJ and the ssaK/U operon, 13 genes encoding components of the type III secretion apparatus of Salmonella Pathogenicity Island 2

Functional analysis of ssaJ and the ssaK/U operon, 13 genes encoding components of the type III secretion apparatus of Salmonella Pathogenicity Island 2

Host adapted serotypes of Salmonella enterica

Genome‐wide identification of tolerance mechanisms toward p‐coumaric acid in Pseudomonas putida

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