• We propose that this alternative transcription factor may be of importance for the invading pathogen to fine-tune its virulence factor production in response to changing host environments. (asm.org)
  • The importance of HlyA as a virulence factor is clear, as it enhances lethal sepsis following intravenous inoculation, but an animal model of progression to urosepsis from a urinary tract infection does not exist ( 8 ). (asm.org)
  • One of the major themes identified in prokaryotic research is that pathogenic bacteria coordinately control gene expression and virulence factor production by complex regulatory circuits in response to alterations in the host milieu. (pnas.org)
  • In this study, the effect of sub-MIC concentrations of the ZnO nanoparticle on the expression of the alpha-hemolysin gene as a significant virulence factor of Staphylococcus aureus is assessed. (ijpsonline.com)
  • This study reveals the function for two large bacterial protein families and their essential role in host fatty acid metabolism by pathogens, and connects Fak to the regulation of virulence factor transcription in S. aureus . (pnas.org)
  • The severe deficiency in α-hemolysin protein secretion in Δ fakA and Δ fakB1 Δ fakB2 mutants coupled with quantitative mRNA measurements showed that fatty acid kinase activity was required to support virulence factor transcription. (pnas.org)
  • These data reveal the function of two conserved gene families, their essential role in the incorporation of host fatty acids by Gram-positive pathogens, and connects fatty acid kinase to the regulation of virulence factor transcription in S. aureus . (pnas.org)
  • One putative virulence factor of H. ducreyi is a pore-forming hemolysin that displays toxicity against human fibroblasts and keratinocytes. (nih.gov)
  • Hemolysin/bacteriocin is a plasmid-encoded protein that generally is accepted as a virulence factor. (medscape.com)
  • The mip (macrophage infectivity potentiator) determinant remains at present the sole established virulence factor. (uni-wuerzburg.de)
  • The protein is a putative virulence factor but most likely not involved in the induction of necrosis. (diva-portal.org)
  • A 46-kDa homodimer protein secreted by this microorganism, the thermostable direct hemolysin (TDH), is considered a major virulence factor involved in bacterial pathogenesis since a high percentage of strains of clinical origin are positive for TDH production. (semanticscholar.org)
  • Extensive research has been conducted to identify virulence factor genes involved in the pathogenesis of E. coli O157:H7 and many genome sequences of E. coli O157:H7 strains have become available to the scientific community. (scirp.org)
  • Here, we provide a comprehensive overview of the research that has been conducted over the first 25 years to identify 394 known or putative virulence factor genes present in the genomes of E. coli O157:H7 strains. (scirp.org)
  • Finally, an examination of the conservation of these 394 virulence factor genes across additional genomes of E. coli O157:H7 is provided which summarizes the first 25 years and 13 genomes of this human pathogen. (scirp.org)
  • Within V. cholerae the 01 and 0139 serogroups were linked with CT and 014 with NAG-ST, in future, other serogroup - virulence factor associations may be found. (open.ac.uk)
  • ADAM10 is also a receptor for α-toxin, a major virulence factor of Staphylococcus aureus . (portlandpress.com)
  • Haemolysin from enterohaemorrhagic Escherichia coli (EHEC-Hly), a putative EHEC virulence factor, belongs to the RTX (repeat-in-toxin) family whose members rapidly inactivate themselves by self-aggregation. (diva-portal.org)
  • Alpha-hemolysin (Hla) is a pore-forming virulence factor produced by S. aureus that can self-assemble into heptameric mushroom-structured pores in target cell membranes, leading to cell lysis and death. (dovepress.com)
  • The O-serogroups of UPEC strains are related to certain virulence factor profile of each strain. (biomedcentral.com)
  • A potential virulence factor that has received little attention is the ability of B. fragilis to produce hemolysins. (uncg.edu)
  • This is the first study showing HlyBA is a virulence factor which plays a role in B. fragilis survival in an intra-abdominal abscess model. (uncg.edu)
  • The E. coli hemolysin is a significant virulence factor in murine models of peritonitis and ascending urinary tract infection, which suggests it is likely to be an important cytotoxin in human, extraintestinal E. coli diseases. (asmscience.org)
  • extracellular protein binds to prothrombin in the host to form a complex called staphylothrombin The protease activity characteristic of thrombin result in the conversion of fibrinogen to fibrin No evidence that it is a virulence factor. (scribd.com)
  • PlcR is a pleiotropic regulator of extracellular virulence factor gene expression in Bacillus thuringiensis. (microbiologyresearch.org)
  • The toxin may be regarded as a virulence factor, since it is crucial for the virulence of L. monocytogenes. (prospecbio.com)
  • The virulence factor α-hemolysin produced by S. aureus lyses perivascular macrophages, which leads to decreased neutrophil transmigration. (centenary.org.au)
  • The ability of S. aureus to cause disease has been attributed to an impressive spectrum of cell-wall-associated (protein A, clumping factors, fibronectin binding proteins, and other adhesive matrix molecules) factors, and extracellular toxins (coagulase, hemolysins, enterotoxins, toxic-shock syndrome toxin 1, exfoliative toxins, and Panton-Valentine leukocidin) as virulence determinants. (mdpi.com)
  • Excepting the toxemic syndromes determined by toxic-shock syndrome toxin 1 (TSST-1), scalded skin syndrome as a result of epidermolytic toxins activity, and food poisoning as a consequence of ingestion of preformed enterotoxins, the pathogenesis of S. aureus is the result of interaction between a variety of host factors and the bacterial virulence determinants [ 1 ]. (mdpi.com)
  • Antivirulence agents against methicillin-resistant Staphylococcus aureus (MRSA) strain USA300, the most widespread community-associated MRSA strain in the United States, were discovered by virtual screening against the response regulator AgrA, which acts as a transcription factor for the expression of several of the most prominent S. aureus toxins and virulence factors involved in pathogenesis. (nih.gov)
  • The small-molecule compounds discovered inhibit the production of the toxins alpha-hemolysin and phenol-soluble modulin α in a dose-dependent manner without inhibiting bacterial growth. (nih.gov)
  • Protein toxins are important virulence factors contributing to neonatal sepsis. (hindawi.com)
  • Clearly, pore-forming toxins are not the sole factors that drive sepsis progression, but they often act in concert with other bacterial effectors, especially in the initial stages of neonatal sepsis manifestation. (hindawi.com)
  • The antimicrobial quality of the local pulmonary environment, for example, the concentration of surfactant, may be important for the metabolic activity in the bacterial community and therefore for the expression of bacterial virulence factors such as bacterial toxins [ 3 ]. (hindawi.com)
  • Many hemolysins are pore-forming toxins (PFT), which are able to cause the lysis of erythrocytes , leukocytes , and platelets by producing pores on the cytoplasmic membrane . (wikipedia.org)
  • γ-Hemolysins are pore-forming toxins in the same family as α-Hemolysin. (wikipedia.org)
  • unlike most commensal E. coli strains, extraintestinal isolates possess genes encoding various combinations of adhesins (P and S fimbriae), iron acquisition systems (e.g., aerobactin and yersiniabactin), host defense avoidance mechanisms (capsule or O-specific antigen), and toxins (e.g., hemolysin and cytonecrotizing factor) ( 13 , 14 , 17 , 42 ). (asm.org)
  • They mainly encompass components of the outer membrane and the periplasm including various virulence factors such as toxins, adhesins, and immunomodulatory molecules. (frontiersin.org)
  • Numerous studies have clearly shown that the delivery of toxins and other virulence factors via OMVs essentially influences their interactions with host cells. (frontiersin.org)
  • Here, we review the OMV-mediated intracellular deployment of toxins and other virulence factors with a special focus on intestinal pathogenic Escherichia coli . (frontiersin.org)
  • The structure proves the heptameric subunit stoichiometry of the alpha-hemolysin oligomer, shows that a glycine-rich and solvent-exposed region of a water-soluble protein can self-assemble to form a transmembrane pore of defined structure, and provides insight into the principles of membrane interaction and transport activity of beta barrel pore-forming toxins. (proteopedia.org)
  • The erythrogenic toxins are responsible for the rash of scarlet fever and are considered an important factor in toxic shock ( 11 ). (ispub.com)
  • In addition to the established toxins two novel factors, which may contribute to the virulence of V. cholerae non-01 and V. mimicus , were found. (open.ac.uk)
  • Our findings provide a general concept for stabilization of RTX toxins and open new insights into the biology of these important virulence factors. (diva-portal.org)
  • Recent progress with its study has slowed down because of the difficulty in deriving the physical structure of the hemolysin protein or other RTX toxins and establishing its precise cytotoxic mechanism and role in pathogenesis of extraintestinal E. coli disease. (asmscience.org)
  • Beta-hemolysin known as an inflammatory inducer is an enzyme with a specific, other than for most of staphylococcal toxins mode of action and its effects depend on sphingomyelinase content in a target cell. (termedia.pl)
  • Gamma-hemolysins are very unique bicomponent pore-forming toxins consisting of S and F class proteins, released as monomers and forming heterooligomers leading to a cation-selective channel formation. (termedia.pl)
  • Hemolysins are extracellular toxic proteins produced by many gram-negative (e.g. (asm.org)
  • The UPEC pore-forming toxin α-hemolysin triggers proteolysis of host proteins to disrupt cell adhesion, inflammatory, and survival pathways. (nih.gov)
  • YmoA modulates the expression of various virulence factors, such as Yop proteins and YadA adhesin, in response to temperature. (ebi.ac.uk)
  • Madrid C, Nieto JM, Juarez A. Role of the Hha/YmoA family of proteins in the thermoregulation of the expression of virulence factors. (ebi.ac.uk)
  • We also discovered that transcription of genes encoding hemolysins, and proteins with inferred roles in iron regulation, transport, and homeostasis, was influenced by growth at 40°C. Thus, GAS profoundly alters gene expression in response to temperature. (pnas.org)
  • Hemolysins or haemolysins are lipids and proteins that cause lysis of red blood cells by disrupting the cell membrane . (wikipedia.org)
  • In molecular biology, the haemolysin expression modulating protein family is a family of proteins. (wikipedia.org)
  • Weight for weight, the cell-surface bound hemolysin, streptolysin S, is one of the most toxic proteins known ( 10 ). (ispub.com)
  • Several genome-wide screens have been conducted to identify host cell factors involved in the pathogenesis of bacterial pathogens whose virulence is dependent on type III secretion systems (T3SSs), nanomachines responsible for the translocation of proteins into host cells. (asm.org)
  • Among the bacterial proteins identified, glutamate decarboxylase, elongation factor-Tu and α-hemolysin are especially noteworthy, as they are implicated in critical bacterial pathways pertaining to survival in acidic environment, protein translation and virulence, respectively. (ajol.info)
  • As alternative sigma factors have been shown to regulate expression of both virulence and virulence-associated genes, these proteins can contribute both directly and indirectly to bacterial virulence. (asm.org)
  • σ 54 forms a distinct subfamily of sigma factors referred to as σ N in almost all species for which these proteins have been characterized to date. (asm.org)
  • Sigma factors are a class of proteins constituting essential dissociable subunits of prokaryotic RNA polymerase. (asm.org)
  • Besides already described putative virulence factors like ankyrin domain proteins, VlrC homologs, and patatin-like proteins, putative novel virulence factors related to those found in intracellular pathogens like Legionella and Mycobacterium are highlighted for the first time in Wolbachia . (g3journal.org)
  • Gelatinase- and hemolysin-producing strains of Enterococcus faecalis have been shown to be virulent in animal models of enterococcal infections. (oup.com)
  • Hemolysin -positive (58 strains ) and hemolysin -negative (2 strains ) Serratia marcescens showed the same LD50 (3 x 107) bacteria ) in a test of virulence for mice . (bvsalud.org)
  • Nearly a century ago, epidemiological studies revealed that UPEC strains were more likely than commensal E. coli to express a hemolytic factor, now known as hemolysin (HlyA) ( 3 ). (asm.org)
  • Subsequent quasi-field tests using various seafood samples (ca. 20 g), each of which was experimentally contaminated with either or both hemolysin-producing strains at an initial density of ca. 5 to 10 viable cells per gram, demonstrated that contamination could be detected within 2 working days. (asm.org)
  • Any of several hemolysins derived from some strains of streptococci. (thefreedictionary.com)
  • R Factors Present in Epidemic Strains on Shigella and Salmonella Species Found in Mexico. (fishpond.com.au)
  • Sparse information is available on the virulence factors of Aeromonas strains isolated from diseased fish, from the environment, and from humans. (asm.org)
  • Strains isolated from the environment do not seem to differ from strains isolated from cases of infection with respect to the prevalence of virulence factors ( 29 ). (asm.org)
  • What is known is that some strains produce hemolysins that can cause some toxicity. (livestrong.com)
  • This study aimed to determine the virulence factors, phylogenetic groups, and the relationships between pathovars and phylogenetic groups of E. coli strains isolated from feces of buffalo calves. (scielo.br)
  • A total of 217 E. coli strains were obtained from feces after culture and were screened by PCR for detection of virulence factors EAST-1, enterohemolysin, Saa, CNF2, F41, F5, STa, intimin, Stx1 and Stx2. (scielo.br)
  • The aim was to identify factors which would distinguish pathogenic from non-pathogenic strains and to establish a correlation, if any, with serogroup. (open.ac.uk)
  • Over 80% of strains produced haemolysin(s) and cytotoxin(s). (open.ac.uk)
  • None of the virulence factors, except CT, was more prevalent in clinical than in environmental strains. (open.ac.uk)
  • We show that GBS invades hAECs and strains lacking the hemolysin repressor CovR/S accelerate amniotic barrier failure and penetrate chorioamniotic membranes in a hemolysin-dependent manner. (rupress.org)
  • The hemolysin occurs less frequently in cystitis strains and only rarely among normal fecal strains. (asmscience.org)
  • In conclusion, the CGC is not the only virulent factor in L. garvieae because strains that lack the CGC are virulent to rainbow trout. (int-res.com)
  • Only in 2% of all of S. aureus 90% of the strains isolated from severe dermonecrotic lesions important factor in necrotizing skin infections. (scribd.com)
  • Delta-hemolysin, a heat-stabile, small protein produced by most Staphylococcus aureus strains acts as a cytolysin but also turned out to be a potent polyclonal activator of lymphocytes. (termedia.pl)
  • Uropathogenic Escherichia coli (UPEC), which are the leading cause of both acute and chronic urinary tract infections, often secrete a labile pore-forming toxin known as α-hemolysin (HlyA). (nih.gov)
  • Although we have known for nearly a century that severe infections stemming from urinary tract infections, including kidney or bloodstream infections are associated with expression of a toxin, hemolysin, from uropathogenic Escherichia coli , how hemolysin functions to enhance virulence is unknown. (asm.org)
  • The E. coli hemolysin is the prototype for a toxin family (RTX family) produced by a wide array of human and animal pathogens. (asm.org)
  • The RTX pore-forming toxin α-hemolysin of uropathogenic Escherichia coli: progress and perspectives. (semanticscholar.org)
  • Hha, along with the chromatin-associated protein H-NS, is involved in the regulation of expression of the toxin alpha-haemolysin in response to osmolarity and temperature [ PMID: 11790731 ]. (ebi.ac.uk)
  • We therefore sought to examine the contribution of the dermonecrotic toxin, hemolysin BL, to the pathogenesis of B. cereus infection in an endophthalmitis system that is highly amenable to study. (asm.org)
  • α-Hemolysin from Staphlococcus aureus is a pore-forming toxin made of seven repeats of an identical monomer arranged in a ring. (proteopedia.org)
  • Cholera toxin (CT) is the factor responsible for the dramatic symptoms of epidemic cholera and is produced by V. cholerae serogroups 01 and 0139. (open.ac.uk)
  • α-hemolysin (Hla), a pore-forming toxin secreted by S. aureus, is very important for pathogenesis. (dovepress.com)
  • The Escherichia coli hemolysin, earlier referred to as the hemolysin, is the best-characterized repeats in toxin (RTX) secreted by a type I exoprotein secretion system. (asmscience.org)
  • protein toxin which creates pores in the membranes hemolytic, but less so than alpha hemolysin. (scribd.com)
  • Alpha-hemolysin is a protein toxin released to host environment as a monomer. (termedia.pl)
  • And while we refer to E. coli O157:H7 and its brethren as Shiga toxin-producing E. coli, there are numerous other virulence factors within these bacteria that allow them to inflict damage. (foodsafetynews.com)
  • These factors include the ability of the bacteria to attach to human cells, transmit toxin into the cells, and secrete powerful inflammatory factors that incite host response that is itself injurious. (foodsafetynews.com)
  • The microaggregates released α-hemolysin toxin, causing localized alveolar injury, as indicated by epithelial dye loss, mitochondrial depolarization, and cytosolic Ca2+ increase. (jci.org)
  • The potential virulence factors of enterococci include production of enterococcal surface protein (Esp), gelatinase, and hemolysin. (oup.com)
  • This family consists of haemolysin expression modulating protein (Hha) from Escherichia coli and its enterobacterial homologues, such as YmoA from Yersinia enterocolitica, and RmoA encoded on the R100 plasmid. (ebi.ac.uk)
  • A human protein required for the second step of pre-mRNA splicing is functionally related to a yeast splicing factor. (ebi.ac.uk)
  • While most hemolysins are protein compounds, some are lipid biosurfactants . (wikipedia.org)
  • Streptococci pyogenes), including adhesions, the M protein, Streptolysin O and Streptolysin S, C5a peptidase, streptokinase, and various superantigens.10, These factors are shared via horizontal gene transfer from S. (thefreedictionary.com)
  • We demonstrate that EHEC-Hly is a biologically active cargo in OMVs with dual roles: a cell-binding protein and a haemolysin. (diva-portal.org)
  • The Plasmodium hemolysin homologue (a protein which pokes holes in red blood cells) is being characterized as a factor contributing to severe anemia. (hopkinsmedicine.org)
  • The isolate, confirmed as serotype 2 by using the coagglutination test (8), did not produce the virulence markers muramidase-released protein, extracellular factor, or the hemolysin suilysin. (thefreedictionary.com)
  • The complex translocation process is influenced by a range of factors including the diameter and inner surface of the pore, the secondary structure of the polymer, and the interactions between the polymer and protein. (bl.uk)
  • σ H has only recently been characterized as a bona fide S. aureus sigma factor, which is involved in the transcriptional regulation of DNA competence factors ( 56 ). (asm.org)
  • In contrast to σ H , the S. aureus alternative transcription factor σ B has been studied intensively. (asm.org)
  • β -Hemolysin from S. aureus , for instance, is a sphingomyelin-specific phospholipase, which cleaves sphingomyelin to ceramide and phosphorylcholine. (hindawi.com)
  • The success of S. aureus as a pathogen is facilitated by production of a litany of virulence factors that promote evasion of the host innate immune system. (jimmunol.org)
  • S. aureus expresses at least four two-component leukotoxins: Panton-Valentine leukocidin (PVL), leukotoxin GH (LukGH), leukotoxin DE, and γ-hemolysin. (jimmunol.org)
  • 10 ), has been used for microbiological identification of Streptococcus agalactiae (group B streptococci [GBS]) since it characteristically synergizes with the secreted β-hemolysin of S. aureus to lyse erythrocytes on blood agar plates ( 11 ). (asm.org)
  • From these locations, S. aureus easily leads to infections ranging from relatively mild cutaneous infections to life-threatening infections such as pneumonia, sepsis, septic arthritis, endocarditis, and osteomyelitis in people predisposed with risk factors 10 . (nature.com)
  • Our data illustrate a previously unrecognized role for perivascular macrophages in neutrophil recruitment to inflamed skin and indicate that S. aureus uses hemolysin-dependent killing of these cells as an immune evasion strategy. (centenary.org.au)
  • The pathogenesis of infection resulting from intravitreal injection of 10 2 CFU of either a clinical ocular isolate of B. cereus producing hemolysin BL (HBL + ) or an isogenic mutant in this trait (HBL − ) was assessed bacteriologically and by slit lamp biomicroscopy, electroretinography, histology, and inflammatory cell enumeration. (asm.org)
  • In order to test the role of the hemolysin in pathogenesis, an isogenic hemolysin-deficient mutant was constructed, designated 35000HP-RSM1. (nih.gov)
  • The pathogenesis of enterococcal infections is poorly understood, but several possible virulence factors exist. (medscape.com)
  • The pathogenesis, pathogenic mechanism, and virulence factors responsible for selected Aeromonas infection in different species are not well understood. (asm.org)
  • Experimental manipulation of the genome to produce mutants with and without specific virulence factors may soon provide greater insight into their respective roles in the pathogenesis of the various streptococcal diseases. (ispub.com)
  • Beta and alpha hemolysins are the most important in pathogenesis of the intramamarian infections (Park et al. (scielo.br)
  • Interestingly, a recent study by Pacheco and colleagues, based on the findings of a genome-wide screen for host factors involved in pathogenesis, suggests a previously unrecognized link between these two important virulence determinants that can be exploited for the development of new therapeutic interventions for this important pathogen ( 1 ). (asm.org)
  • We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. (mdpi.com)
  • While σ B was found to positively control 198 genes by a factor of ≥2 in at least two of the three genetic lineages analyzed, 53 ORFs were repressed in the presence of σ B . Gene products that were found to be influenced by σ B are putatively involved in all manner of cellular processes, including cell envelope biosynthesis and turnover, intermediary metabolism, and signaling pathways. (asm.org)
  • Therefore, σ factors provide an elegant mechanism in eubacteria to allow simultaneous transcription of a variety of genetically unlinked genes, provided all of these genes share the same promoter specificities. (asm.org)
  • Southern hybridization of total DNA from hemolytic isolates to cloned regions of the Escherichia coli alpha-hemolysin (hly) determinant showed clear but incomplete homology between genes encoding production of hemolysins in the four species. (semanticscholar.org)
  • Remarkably, we demonstrated by promoter expression analyses that the reduced hemolysis in the rstB mutant was accompanied by a strong decrease in transcription activities of the three hemolysin genes dly (damselysin), hlyA pl (phobalysin P) and hlyA ch (phobalysin C). Thus, RstB, encoded in the small chromosome, regulates plasmid and chromosomal virulence genes. (frontiersin.org)
  • Genes coding for multiple virulence factors are located together on large blocks of chromosomal DNA known as pathogenicity islands (PAIs) ( 18 ). (asm.org)
  • B. Kunkel, R. Losick, and P. Stragier, "The Bacillus subtilis gene for the developmental transcription factor σ (K) is generated by excision of a dispensable DNA element containing a sporulation recombinase gene," Genes & Development , vol. 4, no. 4, pp. 525-535, 1990. (hindawi.com)
  • By environmental signals or by mutation, or both, de-repression of the genes controlling several virulence factors may lead to the emergence of the GAS clonesmay producing the wide spectrum of GAS diseases. (ispub.com)
  • various genes encode urinary virulence factors. (biomedcentral.com)
  • Genome-wide screens provide an unbiased approach to discover novel genes and pathways underlying biological processes and have been utilized for many decades to identify and characterize bacterial virulence factors. (asm.org)
  • The hemolysin genes were eventually linked to P-type pilin and cytotoxic necrotizing factor-1 genes. (asmscience.org)
  • These two effector genes, along with one other effector-like gene in the same region, are thus good candidates for being pathogenicity factors on citrus. (ufl.edu)
  • As the regulon of a single sigma factor can be composed of hundreds of genes, sigma factors can provide effective mechanisms for simultaneously regulating expression of large numbers of prokaryotic genes. (asm.org)
  • One newly emerging field is identification of the specific roles of alternative sigma factors in regulating expression of virulence genes and virulence-associated genes in bacterial pathogens. (asm.org)
  • A novel method for detecting viable and thermostable direct hemolysin (TDH)-producing or TDH-related hemolysin (TRH)-producing Vibrio parahaemolyticus in seafood was developed. (asm.org)
  • Past epidemiological studies ( 6 , 7 , 16 ) revealed a strong association between gastroenteritis and both thermostable direct hemolysin (TDH) and another hemolysin, termed TDH-related hemolysin (TRH), produced by V. parahaemolyticus . (asm.org)
  • is termed thermostable direct hemolysin (TDH). (kenyon.edu)
  • Vibrio parahaemolyticus thermostable direct hemolysin modulates cytoskeletal organization and calcium homeostasis in intestinal cultured cells. (semanticscholar.org)
  • Association of Vibrio parahaemolyticus thermostable direct hemolysin with lipid rafts is essential for cytotoxicity but not hemolytic activity. (semanticscholar.org)
  • Ca(2+)-independent cytotoxicity of Vibrio parahaemolyticus thermostable direct hemolysin (TDH) on Intestine 407, a cell line derived from human embryonic intestine. (semanticscholar.org)
  • Studies of differential gene expression in response to environmental changes have been conducted by analysis of relatively few target loci that encode proven or putative extracellular virulence factors, and hence have been preselected on the basis of presumed involvement in host-pathogen interactions ( 3 - 6 ). (pnas.org)
  • Thus, LLO permits L. monocytogenes to break out from the phagosomes into the cytosol without harming the plasma membrane of the infected cell, which allows the bacteria to live intracellularly, where they are sheltered from extracellular immune system factors such as the complement system and antibodies. (prospecbio.com)
  • Many bacteria produce hemolysins that can be detected in the laboratory. (wikipedia.org)
  • It is now believed that many clinically relevant fungi also produce hemolysins. (wikipedia.org)
  • We determined the presence of the esp gene and production of gelatinase and hemolysin in 219 E. faecalis isolates from a larger prospective study of 398 patients with enterococcal bacteremia. (oup.com)
  • Thirty-two percent of isolates carried the esp gene, 64% produced gelatinase, and 11% produced hemolysin. (oup.com)
  • However, there is a paucity of information regarding the genetic and molecular aspects of gene expression of its virulence factors during extra-intestinal infections. (uncg.edu)
  • Cloning and primary structure of a new hemolysin gene from Bacillus cereus. (microbiologyresearch.org)
  • The Role of Iron in the Growth and Hemolysin ( Streptolysin S) Production in Streptococcus pyogenes. (thefreedictionary.com)
  • Many hemolysins, such as the oxygen-labile hemolysins (e.g., streptolysin O, pneumolysin O, perfringolysin O, and listeriolysin O) are cholesterol dependent and require the presence of a reducing agent, such as cysteine, in order to obtain hemolytic activity ( 9 ). (asm.org)
  • Bacterial hemolysins found in numerous pathogenic bacteria are often virulence factors. (asm.org)
  • The phlA mutant constructed by allelic exchange remained highly pathogenic after injection in the lepidopteran Spodoptera littoralis , indicating that PhlA hemolysin is not a major virulence determinant. (asm.org)
  • Genomic sequence analysis suggests that many alternative σ factors also exist in a number of other pathogenic species such as Treponema palladium (4 alternative σ factors) ( 21 ), Vibro cholerae (7 alternative σ factors) ( 29 ), Mycobacterium tuberculosis (12 alternative σ factors) ( 12 ), and Pseudomonas aeruginosa (23 alternative σ factors) ( 76 ). (asm.org)
  • There are numerous differences between the two streptococcus species to include their cell wall structure, factors that make them pathogenic or virulence factors, how the organism is acquired, and the resulting diseases. (livestrong.com)
  • 1, required α-hemolysin (hla) as USA300 (LAC agr KO) and USA300 (LAC hla KO) promoted PMN lysis only at high MOIs. (nih.gov)
  • Taken together, these data demonstrate activation of the agr operon in human PMN with the subsequent production of α-hemolysin and PMN lysis. (nih.gov)
  • Hemolysin causes lysis of human erythrocytes, functions as a bacteriocin, and is active against other gram-positive cocci. (medscape.com)
  • [2] Hemolysins can be identified by their ability to lyse red blood cells in vitro . (wikipedia.org)
  • [3] [4] Other hemolysins lyse erythrocytes by hydrolyzing the phospholipids in the bilayer. (wikipedia.org)
  • Bacterial hemolysins can lyse red blood cells (RBCs) and a variety of other cell types, such as mast cells, neutrophils, and polymorphonuclear cells ( 6 ). (asm.org)
  • First, they both produce beta-hemolysis, which means the organisms contain hemolysins, which will lyse red blood cells in agar that contains blood. (livestrong.com)
  • Berger H, Hacker J, Juarez A, Hughes C, Goebel W (1982) Cloning of the chromosomal determinants encoding hemolysin production and mannose resistant hemagglutination in Escherichia coli . (springer.com)
  • Secretion of haemolysin by Escherichia coli. (semanticscholar.org)
  • Especially, OMVs ubiquitously produced and secreted by enterohemorrhagic E. coli (EHEC) appear as a highly advanced mechanism for secretion and simultaneous, coordinated and direct delivery of bacterial virulence factors into host cells. (frontiersin.org)
  • damselae hemolysins and plays critical roles in the pathogenicity of this bacterium. (frontiersin.org)
  • Pathogenicity: Mechanisms and contributing Factors. (fishpond.com.au)
  • Another major chemical that contributes to pathogenicity is hemolysin. (kenyon.edu)
  • For V. mimicus the main virulence factors expressed were aerobactin and NAG-ST. Therefore the pathogenicity of V. cholerae and V. mimicus appears to be multifactorial and it is likely that, as with diarrhoeagenic, E. coli , a heterogeneous pattern of virulence will be found. (open.ac.uk)
  • Alpha-hemolysin contributes to the pathogenicity of piliated digalactoside-binding Eshcerichia coli in the kidney: efficacy of an alpha-hemolysin vaccine in preventing renal injury in the BALB/c mouse model of pyelonephritis. (asmscience.org)
  • To investigate the virulence factors including hemolysin production, β-lactamase production, and biofilm formation. (dovepress.com)
  • Bacterial E. coli isolates were investigated for hemolysin production, biofilm formation, and β-lactamase production. (dovepress.com)
  • Virulence factors analysis showed that 6/10 water isolates and 2/10 clinical isolates were hemolytic, 5/10 water isolates and 3/10 clinical isolates were biofilm formation, and 7/10 water isolates and 4/10 clinical isolates were β-lactamase producer. (dovepress.com)
  • Our study revealed that E. coli isolates from river water exhibit a higher level of hemolysin production, β-lactamase production, and biofilm formation than feces isolates may be due to long adaptation. (dovepress.com)
  • Here, we determined the virulence factors (germination, adherence, biofilm formation, phospholipase and proteinase production) of 16 C. auris isolates and their susceptibilities to 11 drugs belonging to different antifungal classes, including a novel orally bioavailable 1,3-β- d -glucan synthesis inhibitor (SCY-078). (asm.org)
  • To assess the contributions of agr-dependent factors to the fate of organisms in polymorphonuclear neutrophils (PMN), we examined the consequences for organism and host cells of feeding PMN with wild-type CA-MRSA (LAC) or CA-MRSA (LAC agr KO) at different multiplicities of infection (MOIs). (nih.gov)
  • Although the lytic activity of some microbe-derived hemolysins on red blood cells may be of great importance for nutrient acquisition, many hemolysins produced by pathogens do not cause significant destruction of red blood cells during infection. (wikipedia.org)
  • These results indicate that hemolysin BL makes no essential contribution to the severe and rapid course of infection in the endophthalmitis model. (asm.org)
  • Evaluation of an isogenic hemolysin-deficient mutant in the human model of Haemophilus ducreyi infection. (nih.gov)
  • Due to the limitations of this model, the role of the hemolysin at later stages of infection could not be determined. (nih.gov)
  • Strep B produces a few virulence factors like lipoteichoic acid, which contributes the organism's adherence to human cells as the initial step of infection. (livestrong.com)
  • Various host factors, including loss of the normal skin barrier, presence of underlying diseases such as diabetes and acquired immunodeficiency syndrome, or defects in neutrophils function predispose to infection. (pubmedcentralcanada.ca)
  • Bacterial plasmids control resistance to medicines and regulate the synthesis of bacteriocin, enterotoxin, hemolysin, and certain antigens. (thefreedictionary.com)
  • The Escherichia coli hemolysin (HlyA) is a pore-forming exotoxin associated with severe complications of human urinary tract infections. (asm.org)
  • We performed an unbiased forward genetic selection in a mutant library of human monocytic cells, U-937, for host factors involved in HlyA cytotoxicity. (asm.org)
  • Escherichia coli hemolysin is released extracellularly without cleavage of a signal peptide. (semanticscholar.org)
  • Escherichia coli hemolysin is potentially cytotoxic to monocytes, lymphocytes and macrophages , leading them to autolysis and death. (wikipedia.org)
  • Pore formation by the Escherichia coli hemolysin: Evidence for an association-dissociation equilibrium of the pore-forming aggregates. (asmscience.org)
  • Permeability increase induced by Escherichia coli hemolysin A in human macrophages is due to the formation of ionic pores: a patch clamp characterization. (asmscience.org)
  • Compared to beta-hemolysin, it has a higher affinity for phosphocholines with short saturated acyl chains, especially if they have a conical form, whereas cylindrical lipids (e.g., sphingomyelin) hinder its activity. (wikipedia.org)
  • All hemolytic isolates presented beta-hemolysin, and 38% of the non-hemolytic isolates were able to express hemolysins in the presence of a beta-hemolytic strain. (scielo.br)
  • Characterization of the alpha-haemolysin determinant from the human enteropathogenic Escherichia coli O26 plasmid pEO5. (semanticscholar.org)
  • 1985. Nucleotide sequence of an Escherichia coli chromosomal hemolysin. (asmscience.org)
  • Secreted hemolysins were extremely common among clinical isolates of Proteus mirabilis, Proteus vulgaris, and Morganella morganii, and hemolytic activity was either cell associated or cell free. (semanticscholar.org)
  • Hemolysins enable hemolytic microorganisms to directly damage host tissues as well as induce inflammatory responses ( 5 , 7 , 8 ). (asm.org)
  • We describe here the nucleotide sequence and the molecular characterization of the Photorhabdus luminescens phlBA operon, a locus encoding a hemolysin which shows similarities to the Serratia type of hemolysins. (asm.org)
  • The Mapping Malaria Epidemiology in Bangladesh project is characterizing the malaria risk factors from among human-Hemoglobin E, parasite-drug resistance, mosquito-larval habitats and environmental determinants for malaria transmission in two communities with a population of 20,000 people. (hopkinsmedicine.org)
  • Cavalieri SJ, Snyder IS (1982 a) Effect of Escherichia coli alpha-hemolysin on human peripheral leukocyte viability in vitro. (springer.com)
  • At least six alternative σ factors are produced by the enteric bacterium Escherichia coli (reviewed in reference 6 ). (asm.org)
  • The secreted hemolysins of Proteus mirabilis, Proteus vulgaris, and Morganella morganii are genetically related to each other and to the alpha-hemolysin of Escherichia coli. (semanticscholar.org)
  • Epidemiology and Genetics of Hemolysin Formation in Escherichia Coli. (fishpond.com.au)
  • Reiland, H. , Omolo, M. , Johnson, T. and Baumler, D. (2014) A Survey of Escherichia coli O157:H7 Virulence Factors: The First 25 Years and 13 Genomes. (scirp.org)
  • Escherichia coli haemolysin forms voltage-dependent ion channels in lipid membranes. (asmscience.org)
  • There are many factors influencing the toxicity of Aeromonas hydrophila . (kenyon.edu)
  • Genome-wide screens for factors involved in mediating host-pathogen interactions were initially conducted using RNA interference (RNAi)-based technologies ( 2 , 3 ). (asm.org)
  • In addition to the housekeeping sigma subunit, σ 70 or σ A , most bacteria produce one or more additional σ subunits, termed alternative σ factors, which direct the respective E-σ complex to distinct classes of promoters that contain alternative σ factor-specific sequences. (asm.org)
  • This pore consists of seven alpha-hemolysin subunits, which represent the major cytotoxic agent that is freed by this kind of bacterium. (wikipedia.org)
  • Members of the Hha/YmoA/RmoA family act in conjunction with members of the H-NS family, participating in the thermoregulation of different virulence factors and in plasmid transfer [ PMID: 11890540 ]. (ebi.ac.uk)
  • The pPHDD1 plasmid-encoded hemolysins damselysin (Dly) and phobalysin P (PhlyP), and the chromosome-encoded hemolysin phobalysin C (PhlyC) constitute its main virulence factors. (frontiersin.org)
  • These Virulence factors help the organisms to colonize host surfaces, avoid and/or subvert host defense mechanisms, injure and/or invade host cells and tissues, and incite a noxious inflammatory response, thereby leading to clinical disease [ 19 ]. (biomedcentral.com)
  • These virulence factors are acquired over time and are constantly shifting among bacteria as they adopt to their host organisms. (foodsafetynews.com)
  • One way hemolysin lyses erythrocytes is by forming pores in phospholipid bilayers . (wikipedia.org)
  • also known as LukAB), leukotoxin DE, and γ-hemolysin. (jimmunol.org)
  • Our research defines the interaction of hemolysin with the β 2 integrin, a human white cell adhesion molecule, as a potential therapeutic target during urinary tract infections. (asm.org)
  • Urinary infections are treated with antibiotics and removal of predisposing factors when possible, including indwelling catheters. (auanet.org)
  • Haemolysin contributes to virulence of extra-intestinal E. coli infections. (asmscience.org)
  • Racial and genetic factors are increasingly recognized as important predisposing factors associated with severe disease manifestations from a variety of pathogens. (oncologynurseadvisor.com)
  • A total of 60 nosocomial isolates of Serratia marcescens were screened for the presence of markers related to virulence , i. e., cell -bound hemolysin and production of siderophore aerobactin. (bvsalud.org)
  • Antivirulence agents inhibit the production of disease-causing virulence factors but are neither bacteriostatic nor bactericidal. (nih.gov)
  • and (iii) hemolysin production. (asm.org)
  • Not only are the erythrocytes affected by hemolysins, but there are also some effects among other blood cells, such as leucocytes (white blood cells). (wikipedia.org)
  • All of the EUS isolates produced all of the virulence factors investigated, as did also some of the environmental isolates, but the isolates from EUS were unique in their ability to agglutinate fish erythrocytes. (asm.org)
  • Hemolysins - damage erythrocytes, leading to impaired oxygen transport. (vetstream.com)
  • This thesis explores how two molecular dynamics methodologies can simulate the translocation of nucleotides through the nanopore α-hemolysin. (bl.uk)
  • Structure of staphylococcal alpha-hemolysin, a heptameric transmembrane pore. (proteopedia.org)
  • Regulatory effects of Shewanella putrefaciens isolated from shrimp Penaeus orientalis on the virulence factors of Vibrio parahaemolyticus and evaluation of the role of quorum sensing in virulence factors regulation. (semanticscholar.org)
  • Vibrio cholerae non-01 and V. mimicus , isolated from clinical and environmental sources, were examined for factors related to virulence. (open.ac.uk)