Repertoire of the Bacillus thuringiensis Virulence Factors Unrelated to Major Classes of Protein Toxins and Its Role in Specificity of Host-Pathogen Interactions

Bacillus thuringiensis (Bt) is a Gram-positive soil bacteria that infects invertebrates, predominantly of Arthropoda phylum. Due to its immense host range Bt has become a leading producer of biopesticides applied both in biotechnology and agriculture. Cytotoxic effect of Bt, as well as its host specificity, are commonly attributed either to proteinaceous crystal parasporal toxins (Cry and Cyt) produced by bacteria in a stationary phase or to soluble toxins of Vip and Sip families secreted by vegetative cells. At the same time, numerous non-toxin virulence factors of Bt have been discovered, including metalloproteases, chitinases, aminopolyol antibiotics and nucleotide-mimicking moieties. These agents act at each stage of the B. thuringiensis invasion and contribute to cytotoxic properties of Bt strains enhancing toxin activity, ensuring host immune response evasion and participating in extracellular matrix degeneration. In this review we attempt to classify Bt virulence factors unrelated to major groups of protein toxins and discuss their putative role in the establishment of Bt specificity to various groups of insects.

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Proteases fromEntamoebaspp. and Pathogenic Free-Living Amoebae as Virulence Factors

Journal of Tropical Medicine ◽

10.1155/2013/890603 ◽

2013 ◽

Vol 2013 ◽

pp. 1-32 ◽

Cited By ~ 26

Author(s):

Jesús Serrano-Luna ◽

Carolina Piña-Vázquez ◽

Magda Reyes-López ◽

Guillermo Ortiz-Estrada ◽

Mireya de la Garza

Keyword(s):

Immune Response ◽

Extracellular Matrix ◽

Virulence Factors ◽

Free Living ◽

Highly Pathogenic ◽

Cytopathic Effects ◽

Human Parasite ◽

System Components ◽

Protease Expression ◽

Specific Inhibitors

The standard reference for pathogenic and nonpathogenic amoebae is the human parasiteEntamoeba histolytica; a direct correlation between virulence and protease expression has been demonstrated for this amoeba. Traditionally, proteases are considered virulence factors, including those that produce cytopathic effects in the host or that have been implicated in manipulating the immune response. Here, we expand the scope to other amoebae, including less-pathogenicEntamoebaspecies and highly pathogenic free-living amoebae. In this paper, proteases that affect mucin, extracellular matrix, immune system components, and diverse tissues and cells are included, based on studies in amoebic cultures and animal models. We also include proteases used by amoebae to degrade iron-containing proteins because iron scavenger capacity is currently considered a virulence factor for pathogens. In addition, proteases that have a role in adhesion and encystation, which are essential for establishing and transmitting infection, are discussed. The study of proteases and their specific inhibitors is relevant to the search for new therapeutic targets and to increase the power of drugs used to treat the diseases caused by these complex microorganisms.

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The Tripartite Interaction of Host Immunity–Bacillus thuringiensis Infection–Gut Microbiota

Toxins ◽

10.3390/toxins12080514 ◽

2020 ◽

Vol 12 (8) ◽

pp. 514

Author(s):

Shuzhong Li ◽

Surajit De Mandal ◽

Xiaoxia Xu ◽

Fengliang Jin

Keyword(s):

Immune Response ◽

Bacillus Thuringiensis ◽

Gut Microbiota ◽

Insect Resistance ◽

Intestinal Bacteria ◽

Infection Process ◽

Host Immunity ◽

Symbiotic Bacteria ◽

Protein Toxins ◽

Tripartite Interaction

Bacillus thuringiensis (Bt) is an important cosmopolitan bacterial entomopathogen, which produces various protein toxins that have been expressed in transgenic crops. The evolved molecular interaction between the insect immune system and gut microbiota is changed during the Bt infection process. The host immune response, such as the expression of induced antimicrobial peptides (AMPs), the melanization response, and the production of reactive oxygen species (ROS), varies with different doses of Bt infection. Moreover, B. thuringiensis infection changes the abundance and structural composition of the intestinal bacteria community. The activated immune response, together with dysbiosis of the gut microbiota, also has an important effect on Bt pathogenicity and insect resistance to Bt. In this review, we attempt to clarify this tripartite interaction of host immunity, Bt infection, and gut microbiota, especially the important role of key immune regulators and symbiotic bacteria in the Bt killing activity. Increasing the effectiveness of biocontrol agents by interfering with insect resistance and controlling symbiotic bacteria can be important steps for the successful application of microbial biopesticides.

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Host range expansion and the insect immune response

10.1603/ice.2016.93627 ◽

2016 ◽

Author(s):

Angela Smilanich

Keyword(s):

Immune Response ◽

Host Range ◽

Range Expansion ◽

Host Range Expansion ◽

Insect Immune Response

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Differential Exoproteome and Biochemical Characterisation of Neoparamoeba perurans

Microorganisms ◽

10.3390/microorganisms9061258 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1258

Author(s):

Kerrie Ní Ní Dhufaigh ◽

Natasha Botwright ◽

Eugene Dillon ◽

Ian O’Connor ◽

Eugene MacCarthy ◽

...

Keyword(s):

Rainbow Trout ◽

Virulence Factors ◽

Cytotoxic Effect ◽

Differentially Expressed Proteins ◽

Biochemical Characterisation ◽

Key Players ◽

Prolonged Culture ◽

Global Threat ◽

Iron Receptor ◽

Trout Gill

Infection with the protozoan ectoparasite Neoparamoeba perurans, the causative agent of AGD, remains a global threat to salmonid farming. This study aimed to analyse the exoproteome of both an attenuated and virulent N. perurans isolate using proteomics and cytotoxicity testing. A disproportionate presence of proteins from the co-cultured microbiota of N. perurans was revealed on searching an amalgamated database of bacterial, N. perurans and Amoebozoa proteins. LC‑MS/MS identified 33 differentially expressed proteins, the majority of which were upregulated in the attenuated exoproteome. Proteins of putative interest found in both exoproteomes were maltoporin, ferrichrome-iron receptor, and putative ferric enterobactin receptor. Protease activity remained significantly elevated in the attenuated exoproteome compared with the virulent exoproteome. Similarly, the attenuated exoproteome had a significantly higher cytotoxic effect on rainbow trout gill cell line (RTgill W1) cells compared with the virulent exoproteome. The presence of a phosphatase and serine protease in the virulent exoproteome may facilitate AGD infection but do not appear to be key players in causing cytotoxicity. Altogether, this study reveals prolonged culture of N. perurans affects the exoproteome composition in favour of nutritional acquisition, and that the current culturing protocol for virulent N. perurans does not facilitate the secretion of virulence factors.

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Helicobacter pylori virulence factors and the host immune response: implications for therapeutic vaccination

Trends in Microbiology ◽

10.1016/s0966-842x(03)00024-6 ◽

2003 ◽

Vol 11 (3) ◽

pp. 134-138 ◽

Cited By ~ 41

Author(s):

Christian Prinz ◽

Nadia Hafsi ◽

Petra Voland

Keyword(s):

Immune Response ◽

Helicobacter Pylori ◽

Virulence Factors ◽

Host Immune Response ◽

Therapeutic Vaccination

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Host specificity, host range and host preference

Parasitology Today ◽

10.1016/0169-4758(89)90021-5 ◽

1989 ◽

Vol 5 (9) ◽

pp. 298 ◽

Cited By ~ 36

Author(s):

A.J. Lymbery

Keyword(s):

Host Range ◽

Host Specificity ◽

Host Preference

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A Draft Genome Sequence of Pseudomonas syringae pv. tomato T1 Reveals a Type III Effector Repertoire Significantly Divergent from That of Pseudomonas syringae pv. tomato DC3000

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-22-1-0052 ◽

2009 ◽

Vol 22 (1) ◽

pp. 52-62 ◽

Cited By ~ 101

Author(s):

Nalvo F. Almeida ◽

Shuangchun Yan ◽

Magdalen Lindeberg ◽

David J. Studholme ◽

David J. Schneider ◽

...

Keyword(s):

Host Range ◽

Host Specificity ◽

Pseudomonas Syringae ◽

Genome Sequence ◽

Draft Genome ◽

Draft Genome Sequence ◽

Tomato Dc3000 ◽

Type Iii ◽

Host Range Determination ◽

Range Determination

Diverse gene products including phytotoxins, pathogen-associated molecular patterns, and type III secreted effectors influence interactions between Pseudomonas syringae strains and plants, with additional yet uncharacterized factors likely contributing as well. Of particular interest are those interactions governing pathogen-host specificity. Comparative genomics of closely related pathogens with different host specificity represents an excellent approach for identification of genes contributing to host-range determination. A draft genome sequence of Pseudomonas syringae pv. tomato T1, which is pathogenic on tomato but nonpathogenic on Arabidopsis thaliana, was obtained for this purpose and compared with the genome of the closely related A. thaliana and tomato model pathogen P. syringae pv. tomato DC3000. Although the overall genetic content of each of the two genomes appears to be highly similar, the repertoire of effectors was found to diverge significantly. Several P. syringae pv. tomato T1 effectors absent from strain DC3000 were confirmed to be translocated into plants, with the well-studied effector AvrRpt2 representing a likely candidate for host-range determination. However, the presence of avrRpt2 was not found sufficient to explain A. thaliana resistance to P. syringae pv. tomato T1, suggesting that other effectors and possibly type III secretion system–independent factors also play a role in this interaction.

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