scholarly journals Evolution of CDC42, a putative virulence factor triggering meristematic growth in black yeasts

2008 ◽  
Vol 61 ◽  
pp. 121-129 ◽  
Author(s):  
S. Deng ◽  
A.H.G. Gerrits van den Ende ◽  
A.F.J. Ram ◽  
M. Arentshorst ◽  
Y. Gräser ◽  
...  
Keyword(s):  
Virulence Factor ◽  
Black Yeasts ◽  
Putative Virulence Factor ◽  
Meristematic Growth

scholarly journals Characterization of C3larvinA, a novel RhoA-targeting ADP-ribosyltransferase toxin produced by the honey bee pathogen, Paenibacillus larvae

2020 ◽  
Vol 40 (1) ◽  
Author(s):  
Madison Turner ◽  
Olivier Tremblay ◽  
Kayla A. Heney ◽  
Miguel R. Lugo ◽  
Julia Ebeling ◽  
...  
Keyword(s):  
Virulence Factor ◽  
Catalytic Mechanism ◽  
Homology Model ◽  
Covalent Modification ◽  
Paenibacillus Larvae ◽  
Bacterial Toxin ◽  
Transferase Activity ◽  
Putative Virulence Factor ◽  
Cellular Effects ◽  
Biological Target

Abstract C3larvinA is a putative virulence factor produced by Paenibacillus larvae enterobacterial-repetitive-intergenic-consensus (ERIC) III/IV (strain 11-8051). Biochemical, functional and structural analyses of C3larvinA revealed that it belongs to the C3-like mono-ADP-ribosylating toxin subgroup. Mammalian RhoA was the target substrate for its transferase activity suggesting that it may be the biological target of C3larvinA. The kinetic parameters of the NAD+ substrate for the transferase (KM = 75 ± 10 µM) and glycohydrolase (GH) (KM = 107 ± 20 µM) reactions were typical for a C3-like bacterial toxin, including the Plx2A virulence factor from Paenibacillus larvae ERIC I. Upon cytoplasmic expression in yeast, C3larvinA caused a growth-defective phenotype indicating that it is an active C3-like toxin and is cytotoxic to eukaryotic cells. The catalytic variant of the Q187-X-E189 motif in C3larvinA showed no cytotoxicity toward yeast confirming that the cytotoxicity of this factor depends on its enzymatic activity. A homology consensus model of C3larvinA with NAD+ substrate was built on the structure of Plx2A, provided additional confirmation that C3larvinA is a member of the C3-like mono-ADP-ribosylating toxin subgroup. A homology model of C3larvinA with NADH and RhoA was built on the structure of the C3cer-NADH-RhoA complex which provided further evidence that C3larvinA is a C3-like toxin that shares an identical catalytic mechanism with C3cer from Bacillus cereus. C3larvinA induced actin cytoskeleton reorganization in murine macrophages, whereas in insect cells, vacuolization and bi-nucleated cells were observed. These cellular effects are consistent with C3larvinA disrupting RhoA function by covalent modification that is shared among C3-like bacterial toxins.

scholarly journals A Novel Methicillin-ResistantStaphylococcus aureust11469 and a Poultry Endemic Strain t002 (ST5) Are Present in Chicken in Ebonyi State, Nigeria

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Amos Nworie ◽  
Azi S. Onyema ◽  
Simon I. Okekpa ◽  
Michael O. Elom ◽  
Nse O. Umoh ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factor ◽  
Molecular Typing ◽  
Staphylococcal Infection ◽  
Sequence Type ◽  
Antimicrobial Use ◽  
Putative Virulence Factor ◽  
The Novel ◽  
Pathogenic Potential ◽  
Endemic Strain

Background. The changing epidemiology of methicillin-resistantStaphylococcus aureus(MRSA) from a hospital-associated pathogen to an organism commonly found in the community and in livestock reflects an organism well-equipped to survive in diverse environments and adjust to different environmental conditions including antimicrobial use.Methods. We investigated the molecular epidemiology ofS. aureusand MRSA in poultry in Ebonyi State, Nigeria. Samples were collected from 1800 birds on 9 different farms within the state. Positive isolates were tested for antibiotic susceptibility and molecular typing.Results. Prevalence in birds was 13.7% (247/1800). MRSA prevalence in poultry was 0.8%. The prevalence of MRSA in broilers and layers was 1.2% and 0.4%, respectively. All tested isolates were susceptible to vancomycin. Molecular analysis of the isolates revealed 3spatypes: t002, t084, and a novelspatype, t11469. The novelspatype t11469 belonged to sequence type ST5.Conclusion. The detection of t002 in chicken suggests the presence of livestock-associated MRSA in poultry in Ebonyi State. The detection of the newspatype t11469 in poultry that has not been characterised to ascertain its pathogenic potential remains a cause for concern, especially as some were found to carry PVL genes, a putative virulence factor in staphylococcal infection.

scholarly journals Comparative genome analysis of 24 bovine-associatedStaphylococcusisolates with special focus on the putative virulence genes

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4560 ◽  
Author(s):  
Silja Åvall-Jääskeläinen ◽  
Suvi Taponen ◽  
Ravi Kant ◽  
Lars Paulin ◽  
Jochen Blom ◽  
...  
Keyword(s):  
Virulence Factor ◽  
Virulence Genes ◽  
Bovine Mastitis ◽  
Virulence Gene ◽  
Subclinical Mastitis ◽  
Special Focus ◽  
Putative Virulence Factor ◽  
Cumulative Number ◽  
Genome Sequences ◽  
Potential Association

Non-aureus staphylococci (NAS) are most commonly isolated from subclinical mastitis. Different NAS species may, however, have diverse effects on the inflammatory response in the udder. We determined the genome sequences of 20 staphylococcal isolates from clinical or subclinical bovine mastitis, belonging to the NAS speciesStaphylococcus agnetis, S. chromogenes,andS. simulans, and focused on the putative virulence factor genes present in the genomes. For comparison we used our previously published genome sequences of fourS. aureusisolates from bovine mastitis. The pan-genome and core genomes of the non-aureus isolates were characterized. After that, putative virulence factor orthologues were searchedin silico. We compared the presence of putative virulence factors in the NAS species andS. aureusand evaluated the potential association between bacterial genotype and type of mastitis (clinical vs. subclinical). The NAS isolates had much less virulence gene orthologues than theS. aureusisolates. One third of the virulence genes were detected only inS. aureus. About 100 virulence genes were present in allS. aureusisolates, compared to about 40 to 50 in each NAS isolate.S. simulansdiffered the most. Several of the virulence genes detected among NAS were harbored only byS. simulans, but it also lacked a number of genes present both inS. agnetisandS. chromogenes. The type of mastitis was not associated with any specific virulence gene profile. It seems that the virulence gene profiles or cumulative number of different virulence genes are not directly associated with the type of mastitis (clinical or subclinical), indicating that host derived factors such as the immune status play a pivotal role in the manifestation of mastitis.

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