Cell-Penetrating Antimicrobial Peptides Derived from an Atypical Staphylococcal δ-Toxin

The continued emergence and global distribution of infections caused by antimicrobial-resistant pathogens fuel our perpetual need for new or alternative therapies. Here, we present the discovery and initial characterization of bacterial cell-penetrating AMPs that were based on a family of virulence factors.

Download Full-text

Insect Gut Symbiont Susceptibility to Host Antimicrobial Peptides Caused by Alteration of the Bacterial Cell Envelope

Journal of Biological Chemistry ◽

10.1074/jbc.m115.651158 ◽

2015 ◽

Vol 290 (34) ◽

pp. 21042-21053 ◽

Cited By ~ 30

Author(s):

Jiyeun Kate Kim ◽

Dae Woo Son ◽

Chan-Hee Kim ◽

Jae Hyun Cho ◽

Roberta Marchetti ◽

...

Keyword(s):

Antimicrobial Peptides ◽

Bacterial Cell ◽

Biochemical Characterization ◽

Cultured Cells ◽

Cell Envelope ◽

Bacterial Cell Envelope ◽

Symbiotic Interactions ◽

Gut Symbionts ◽

Insect Gut

The molecular characterization of symbionts is pivotal for understanding the cross-talk between symbionts and hosts. In addition to valuable knowledge obtained from symbiont genomic studies, the biochemical characterization of symbionts is important to fully understand symbiotic interactions. The bean bug (Riptortus pedestris) has been recognized as a useful experimental insect gut symbiosis model system because of its cultivatable Burkholderia symbionts. This system is greatly advantageous because it allows the acquisition of a large quantity of homogeneous symbionts from the host midgut. Using these naïve gut symbionts, it is possible to directly compare in vivo symbiotic cells with in vitro cultured cells using biochemical approaches. With the goal of understanding molecular changes that occur in Burkholderia cells as they adapt to the Riptortus gut environment, we first elucidated that symbiotic Burkholderia cells are highly susceptible to purified Riptortus antimicrobial peptides. In search of the mechanisms of the increased immunosusceptibility of symbionts, we found striking differences in cell envelope structures between cultured and symbiotic Burkholderia cells. The bacterial lipopolysaccharide O antigen was absent from symbiotic cells examined by gel electrophoretic and mass spectrometric analyses, and their membranes were more sensitive to detergent lysis. These changes in the cell envelope were responsible for the increased susceptibility of the Burkholderia symbionts to host innate immunity. Our results suggest that the symbiotic interactions between the Riptortus host and Burkholderia gut symbionts induce bacterial cell envelope changes to achieve successful gut symbiosis.

Download Full-text

Group A streptococcal puerperal sepsis: initial characterization of virulence factors in association with clinical parameters

Journal of Reproductive Immunology ◽

10.1016/j.jri.2009.06.126 ◽

2009 ◽

Vol 82 (1) ◽

pp. 74-83 ◽

Cited By ~ 17

Author(s):

Janice L.B. Byrne ◽

Kjersti M. Aagaard-Tillery ◽

Jason L. Johnson ◽

Larry J. Wright ◽

Robert M. Silver

Keyword(s):

Virulence Factors ◽

Clinical Parameters ◽

Puerperal Sepsis ◽

Initial Characterization ◽

Group A

Download Full-text

Identification and characterization of two transmembrane proteins required for virulence of Ustilago maydis

10.1101/2021.03.09.434588 ◽

2021 ◽

Author(s):

Paul Weiland ◽

Florian Altegoer

Keyword(s):

Virulence Factors ◽

Biochemical Analysis ◽

Transmembrane Proteins ◽

Ustilago Maydis ◽

Effector Proteins ◽

Smut Fungi ◽

Initial Characterization ◽

Associated Proteins ◽

Identification And Characterization

AbstractSmut fungi comprise a large group of biotrophic phytopathogens infecting important crops such as wheat and corn. Through the secretion of effector proteins, the fungus actively suppresses plant immune reactions and modulates its host’s metabolism. Consequently, how soluble effector proteins contribute to virulence is already characterized in a range of phytopathogens. However, membrane-associated virulence factors have been much less studied to date. Here, we investigated six transmembrane (TM) proteins that show elevated gene expression during biotrophic development of the maize pathogen Ustilago maydis. We show that two of the six proteins, named Vmp1 and Vmp2 (virulence-associated membrane protein), are essential for the full virulence of U. maydis. The deletion of the corresponding genes lead to a substantial attenuation in the virulence of U. maydis. Furthermore, both are conserved in various related smuts and contain no domains of known function. Our biochemical analysis clearly shows that Vmp1 and Vmp2 are membrane-associated proteins, potentially localizing to the U. maydis plasma membrane. Mass photometry and light scattering suggest that Vmp1 mainly occurs as a monomer, while Vmp2 is dimeric. Notably, the large and partially unstructured C-terminal domain of Vmp2 is crucial for virulence while not contributing to dimerization. Taken together, we here provide an initial characterization of two membrane proteins as virulence factors of U. maydis.

Download Full-text

Identification and Characterization of Two Transmembrane Proteins Required for Virulence of Ustilago maydis

Frontiers in Plant Science ◽

10.3389/fpls.2021.669835 ◽

2021 ◽

Vol 12 ◽

Author(s):

Paul Weiland ◽

Florian Altegoer

Keyword(s):

Virulence Factors ◽

Biochemical Analysis ◽

Transmembrane Proteins ◽

Ustilago Maydis ◽

Effector Proteins ◽

Smut Fungi ◽

Initial Characterization ◽

Associated Proteins ◽

Identification And Characterization

Smut fungi comprise a large group of biotrophic phytopathogens infecting important crops such as wheat and corn. Through the secretion of effector proteins, the fungus actively suppresses plant immune reactions and modulates its host’s metabolism. Consequently, how soluble effector proteins contribute to virulence is already characterized in a range of phytopathogens. However, membrane-associated virulence factors have been much less studied to date. Here, we investigated six transmembrane (TM) proteins that show elevated gene expression during biotrophic development of the maize pathogen Ustilago maydis. We show that two of the six proteins, named Vmp1 and Vmp2 (virulence-associated membrane protein), are essential for the full virulence of U. maydis. The deletion of the corresponding genes leads to a substantial attenuation in the virulence of U. maydis. Furthermore, both are conserved in various related smuts and contain no domains of known function. Our biochemical analysis clearly shows that Vmp1 and Vmp2 are membrane-associated proteins, potentially localizing to the U. maydis plasma membrane. Mass photometry and light scattering suggest that Vmp1 mainly occurs as a monomer, while Vmp2 is dimeric. Notably, the large and partially unstructured C-terminal domain of Vmp2 is crucial for virulence while not contributing to dimerization. Taken together, we here provide an initial characterization of two membrane proteins as virulence factors of U. maydis.

Download Full-text