scholarly journals The Secretion of Toxins and Other Exoproteins of Cronobacter: Role in Virulence, Adaption, and Persistence

2020 ◽  
Vol 8 (2) ◽  
pp. 229 ◽  
Author(s):  
Hyein Jang ◽  
Gopal R. Gopinath ◽  
Athmanya Eshwar ◽  
Shabarinath Srikumar ◽  
Scott Nguyen ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Human Disease ◽  
Pathogenic Bacteria ◽  
Eukaryotic Cell ◽  
Human Pathogens ◽  
Wide Range ◽  
Cell Processes ◽  
Cronobacter Species ◽  
Foodborne Pathogenic Bacteria ◽  
Species Specific

Cronobacter species are considered an opportunistic group of foodborne pathogenic bacteria capable of causing both intestinal and systemic human disease. This review describes common virulence themes shared among the seven Cronobacter species and describes multiple exoproteins secreted by Cronobacter, many of which are bacterial toxins that may play a role in human disease. The review will particularly concentrate on the virulence factors secreted by C. sakazakii, C. malonaticus, and C. turicensis, which are the primary human pathogens of interest. It has been discovered that various species-specific virulence factors adversely affect a wide range of eukaryotic cell processes including protein synthesis, cell division, and ion secretion. Many of these factors are toxins which have been shown to also modulate the host immune response. These factors are encoded on a variety of mobile genetic elements such as plasmids and transposons; this genomic plasticity implies ongoing re-assortment of virulence factor genes which has complicated our efforts to categorize Cronobacter into sharply defined genomic pathotypes.

scholarly journals Plant thionins: structure, biological functions and potential use in biotechnology

2018 ◽  
Vol 22 (6) ◽  
pp. 667-675 ◽  
Author(s):  
T. I. Odintsova ◽  
M. P. Slezina ◽  
E. A. Istomina
Keyword(s):  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Biological Activities ◽  
Three Dimensional ◽  
Amino Acid Sequences ◽  
Lipid Transfer ◽  
Human Pathogens ◽  
Candida Spp ◽  
Wide Range ◽  
Bacteria And Fungi

Antimicrobial peptides (AMPs) are important components of defense system in both plants and animals. They represent an ancient mechanism of innate immunity providing rapid first line of defense against pathogens. Plant AMPs are classified into several families: thionins, defensins, nonspecific lipid-transfer proteins, hevein- and knottin-type peptides, hairpinins and macrocyclic peptides (cyclotides). The review focuses on the thionin family. Thionins comprise a plant-specific AMP family that consists of short (~5 kDA) cysteine-rich peptides containing 6 or 8 cysteine residues with antimicrobial and toxic properties. Based on similarity in amino acid sequences and the arrangement of disulphide bonds, five structural classes of thionins are discriminated. The three-dimensional structures of a number of thionins were determined. The amphipathic thionin molecule resembles the Greek letter Г, in which the long arm is formed by two antiparallel α-helices, while the short one, by two parallel β-strands. The residues responsible for the antimicrobial activity of thionins were identified. Thionins are synthesized as precursor proteins consisting of a signal peptide, the mature peptide region and the C-terminal prodomain. Thionins protect plants from pathogenic bacteria and fungi acting directly on the membranes of microorganisms at micromolar concentrations, although their precise mode of action remains unclear. In addition to plant pathogens, thionins inhibit growth of a number of human pathogens and opportunistic microorganisms, such as Candida spp., Saccharomyces cerevisiae, Fusarium solani, Staphylococcus aureus and Escherichia coli. Thionins are toxic to different types of cells including mammalian cancer cell lines. Transgenic plants expressing thionin genes display enhanced resistance to pathogens. A wide range of biological activities makes thionins promising candidates for practical application in agriculture and medicine.

scholarly journals Whole Genome Sequence Analysis of Brucella melitensis Phylogeny and Virulence Factors

2021 ◽  
Vol 12 (3) ◽  
pp. 698-710
Author(s):  
Peter Rabinowitz ◽  
Bar Zilberman ◽  
Yair Motro ◽  
Marilyn C. Roberts ◽  
Alex Greninger ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Pathogenic Bacteria ◽  
Virulence Genes ◽  
Brucella Melitensis ◽  
Geographic Region ◽  
Clinical Severity ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Pan Genome ◽  
Wide Range

Brucellosis has a wide range of clinical severity in humans that remains poorly understood. Whole genome sequencing (WGS) analysis may be able to detect variation in virulence genes. We used Brucella melitensis sequences in the NCBI Sequence Read Archive (SRA) database to assemble 248 whole genomes, and additionally, assembled 27 B. melitensis genomes from samples of human patients in Southern Israel. We searched the 275 assembled genomes for the 43 B. melitensis virulence genes in the Virulence Factors of Pathogenic Bacteria Database (VFDB) and 10 other published putative virulence genes. We explored pan-genome variation across the genomes and in a pilot analysis, explored single nucleotide polymorphism (SNP) variation among the ten putative virulence genes. More than 99% of the genomes had sequences for all Brucella melitensis virulence genes included in the VFDB. The 10 other virulence genes of interest were present across all the genomes, but three of these genes had SNP variation associated with particular Brucella melitensis genotypes. SNP variation was also seen within the Israeli genomes obtained from a small geographic region. While the Brucella genome is highly conserved, this novel and large whole genome study of Brucella demonstrates the ability of whole genome and pan-genome analysis to screen multiple genomes and identify SNP variation in both known and novel virulence genes that could be associated with differential disease virulence. Further development of whole genome techniques and linkage with clinical metadata on disease outcomes could shed light on whether such variation in the Brucella genome plays a role in pathogenesis.

scholarly journals Small RNA Regulation of Virulence in Pathogenic Escherichia coli

2021 ◽  
Vol 10 ◽  
Author(s):  
Brandon M. Sy ◽  
Jai J. Tree
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Regulation ◽  
Virulence Factors ◽  
Small Rna ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Human Pathogens ◽  
Rna Regulation ◽  
Wide Range ◽  
Post Transcriptional Regulation

Enteric and extraintestinal pathotypes of Escherichia coli utilize a wide range of virulence factors to colonize niches within the human body. During infection, virulence factors such as adhesins, secretions systems, or toxins require precise regulation and coordination to ensure appropriate expression. Additionally, the bacteria navigate rapidly changing environments with fluctuations in pH, temperature, and nutrient levels. Enteric pathogens utilize sophisticated, interleaved systems of transcriptional and post-transcriptional regulation to sense and respond to these changes and modulate virulence gene expression. Regulatory small RNAs and RNA-binding proteins play critical roles in the post-transcriptional regulation of virulence. In this review we discuss how the mosaic genomes of Escherichia coli pathotypes utilize small RNA regulation to adapt to their niche and become successful human pathogens.

scholarly journals Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria

2015 ◽  
Vol 81 (16) ◽  
pp. 5604-5612 ◽  
Author(s):  
Ellen Lambrecht ◽  
Julie Baré ◽  
Natascha Chavatte ◽  
Wim Bert ◽  
Koen Sabbe ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Acanthamoeba Castellanii ◽  
Bacterial Survival ◽  
Free Living ◽  
Active Growth ◽  
Content Type ◽  
Foodborne Pathogenic Bacteria ◽  
Adverse Environmental Conditions ◽  
Species Specific

ABSTRACTThe production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica,Escherichia coli,Yersinia enterocolitica, andListeria monocytogenes) survive inside cysts of the ubiquitous amoebaAcanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, withSalmonella entericasurviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed.

scholarly journals Mechanisms and functions of endocytosis in T cells

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
John C. Charpentier ◽  
Philip D. King
Keyword(s):  
T Cell ◽  
Cell Biology ◽  
Cell Receptor ◽  
Eukaryotic Cell ◽  
Cell Functions ◽  
Wide Range ◽  
T Cell Biology ◽  
T Cell Receptor Signaling ◽  
Cell Processes ◽  
Cell Receptor Signaling

AbstractOnce thought of primarily as a means to neutralize pathogens or to facilitate feeding, endocytosis is now known to regulate a wide range of eukaryotic cell processes. Among these are regulation of signal transduction, mitosis, lipid homeostasis, and directed migration, among others. Less well-appreciated are the roles various forms of endocytosis plays in regulating αβ and, especially, γδ T cell functions, such as T cell receptor signaling, antigen discovery by trogocytosis, and activated cell growth. Herein we examine the contribution of both clathrin-mediated and clathrin-independent mechanisms of endocytosis to T cell biology.

scholarly journals Toxicity Evaluation and Antimicrobial Activity of Purified Pyocyanin from Pseudomonas aeruginosa

2020 ◽  
Vol 10 (6) ◽  
pp. 6974-6990
Keyword(s):  
Antimicrobial Activity ◽  
Foodborne Pathogens ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Inhibition Zone ◽  
Mouse Bioassay ◽  
Wide Range ◽  
Mycotoxigenic Fungi ◽  
Foodborne Pathogenic Bacteria ◽  
Mic Value

Pigments from microbial sources considered a promising approach in food industry applications as a food colorant and biopreservatives agents. This study aims to evaluate the antimicrobial activity of purified pyocyanin against foodborne pathogens and study the safety of pyocyanin by toxicity determination. Purification and structure elucidation of pyocyanin was carried out using a UV-Vis spectrophotometer, Fourier Transform Infra-Red Spectroscopy (FTIR) and GC-MS analysis. Pyocyanin showed antibacterial activity against 9 species of foodborne pathogenic bacteria with a zone of inhibition from 10.8 to 22.6 mm, and minimum inhibitory concentration (MIC) value ranged between 33.3 to 233.3 µg ml-1. Also, pyocyanin has antifungal activity against 10 mycotoxigenic fungi strains with inhibition zone value ranged from 7.0 to 17.6 mm and MIC value from 58.3 to 250 µg ml-1. No toxicity was observed on shrimp nauplii up to 50 µg ml-1 for 12 and 24 h of exposure and up to 100 µg ml-1 for 12 h. Also, no toxicity was recorded with pyocyanin using mouse bioassay up to 750 µg ml-1, while 1000 µg ml-1 observed toxicity equal to 3.28 MU (mouse unit). Pyocyanin had antimicrobial activity against a wide range of foodborne pathogenic bacteria and mycotoxigenic fungi. Consequently, pyocyanin can be used as a cheap and safe source in the food industry and pharmaceutical applications.

Antibiofilm Action of ZnO, SnO2 and CeO2 Nanoparticles Towards Grampositive Biofilm Forming Pathogenic Bacteria

2020 ◽  
Vol 14 (3) ◽  
pp. 239-249 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Jang-Won Lee ◽  
Dung N.T. Pham ◽  
Mohammad M. Khan ◽  
Seul-Ki Park ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Metallic Nanoparticles ◽  
Pathogenic Bacteria ◽  
Antibacterial Properties ◽  
Antibiofilm Activity ◽  
Amyloid Protein ◽  
Human Pathogens ◽  
Zno Nps ◽  
Wide Range

Background: The ability to form biofilm and produce several virulence factors has caused numerous human pathogens to become tremendously resistant towards traditional antibiotic treatments, thus, new alternative strategies are urgently in demand. One of the strategies that have recently been developed involves the application of metallic Nanoparticles (NPs). Up to the present, promising results in terms of antimicrobial and antibiofilm activities have been observed in a wide range of metal NPs. Methods: The present study has selected three metal oxides such as ZnO, SnO2 and CeO2 NPs to comparatively investigate their antibiofilm and antibacterial properties against two Gram-positive human pathogens, which are Listeria monocytogenes and Staphylococcus aureus. Result: The anti-biofilm activities of ZnO, SnO2 and CeO2 NPs against S. aureus and L. monocytogenes were assayed by crystal violet staining and confirmed by microscopic visualization using SEM. The synthesis of amyloid protein by S. aureus and exopolysaccharide by L. monocytogenes in the presence of ZnO, SnO2 and CeO2 NPs was evaluated by Congo red assay. Conclusion: Overall, these results indicated that ZnO, SnO2 and CeO2 NPs can be considered as potential agents for treating the infections caused by L. monocytogenes and S. aureus, especially those associated with biofilm formation. Based on the present study, further studies are required to understand their mechanisms at both phenotypic and molecular levels, as well as their in vivo cytotoxicity, thereby enabling the applications of these metal oxide NPs in biomedical fields and food industry. Discussion: Results have shown that ZnO, SnO2 and CeO2 NPs effectively inhibited biofilm formation of both L. monocytogenes and S. aureus. The microscopic analysis also confirmed the antibiofilm activity of these NPs. It was also found that only ZnO NPs inhibited cell growth as well as the production of amyloid protein in S. aureus.

scholarly journals Revisiting Bacterial Ubiquitin Ligase Effectors: Weapons for Host Exploitation

2018 ◽  
Vol 19 (11) ◽  
pp. 3576 ◽  
Author(s):  
Antonio Pisano ◽  
Francesco Albano ◽  
Eleonora Vecchio ◽  
Maurizio Renna ◽  
Giuseppe Scala ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Pathogenic Bacteria ◽  
Eukaryotic Cell ◽  
Vesicular Trafficking ◽  
Cell Physiology ◽  
Regulatory Processes ◽  
Ubiquitin System ◽  
Wide Range ◽  
Ubiquitination System ◽  
Host Exploitation

Protein ubiquitylation plays a central role in eukaryotic cell physiology. It is involved in several regulatory processes, ranging from protein folding or degradation, subcellular localization of proteins, vesicular trafficking and endocytosis to DNA repair, cell cycle, innate immunity, autophagy, and apoptosis. As such, it is reasonable that pathogens have developed a way to exploit such a crucial system to enhance their virulence against the host. Hence, bacteria have evolved a wide range of effectors capable of mimicking the main players of the eukaryotic ubiquitin system, in particular ubiquitin ligases, by interfering with host physiology. Here, we give an overview of this topic and, in particular, we detail and discuss the mechanisms developed by pathogenic bacteria to hijack the host ubiquitination system for their own benefit.

scholarly journals Structure of the Potential Virulence Factor from Francisella tularensis Shows Unexpected Presence of the SHS2 Motif and Similarity to Other Bacterial Virulence Factors

2022 ◽  
Author(s):  
Janette Chammas ◽  
Mallika Iyer ◽  
George Minasov ◽  
Ludmilla Shuvalova ◽  
Wayne Anderson ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Francisella Tularensis ◽  
Virulence Factor ◽  
Pathogenic Bacteria ◽  
Large Family ◽  
Structural Motif ◽  
Dimensional Structure ◽  
Human Pathogens ◽  
Recognition Sequence ◽  
Potential Virulence Factor

Pathogenic bacteria attack their host by secreting virulence factors that in various ways interrupt host defenses and damage their cells. Functions of many virulence factors, even from well-studied pathogens, are still unknown. Francisella tularensis is a class A pathogen and a causative agent of tularemia, a disease that is lethal without proper treatment. Here we report the three-dimensional structure and preliminary analysis of the potential virulence factor identified by the transcriptomic analysis of the F. tularensis disease models that is encoded by the FTT_1539 gene. The structure of the FTT_1539 protein contains two sets of three stranded antiparallel beta sheets, with a helix placed between the first and the second beta strand in each sheet. This structural motif, previously seen in virulence factors from other pathogens, was named the SHS2 motif and identified to play a role in protein-protein interactions and small molecule recognition. Sequence and structure analysis identified FTT_1539 as a member of a large family of secreted proteins from a broad range of pathogenic bacteria, such as Helicobacter pylori and Mycobacterium tuberculosis. While the specific function of the proteins from this class is still unknown, their similarity to the H. pylori Tip-α protein that induces TNF-a and other chemokines through NF-kB activation suggests the existence of a common pathogen-host interference mechanism shared by multiple human pathogens.

scholarly journals Burkholderia cepaciaComplex: Emerging Multihost Pathogens Equipped with a Wide Range of Virulence Factors and Determinants

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sílvia A. Sousa ◽  
Christian G. Ramos ◽  
Jorge H. Leitão
Keyword(s):  
Virulence Factors ◽  
Burkholderia Cepacia ◽  
Multidrug Resistant ◽  
Human Pathogens ◽  
Closely Related Species ◽  
Oncological Patients ◽  
Wide Range ◽  
Life Threatening ◽  
Novel Therapeutic Strategies

TheBurkholderia cepaciacomplex (Bcc) comprises at least 17 closely-related species of theβ-proteobacteria subdivision, widely distributed in natural and man-made inhabitats. Bcc bacteria are endowed with an extraordinary metabolic diversity and emerged in the 1980s as life-threatening and difficult-to-treat pathogens among patients suffering from cystic fibrosis. More recently, these bacteria became recognized as a threat to hospitalized patients suffering from other diseases, in particular oncological patients. In the present paper, we review these and other traits of Bcc bacteria, as well as some of the strategies used to identify and validate the virulence factors and determinants used by these bacteria. The identification and characterization of these virulence factors is expected to lead to the design of novel therapeutic strategies to fight the infections caused by these emergent multidrug resistant human pathogens.

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