Analysis of genes encoding for proteolytic enzymes and cytotoxic proteins as virulence factors of Piscirickettsia salmonis in SHK‐1 cells

2021 ◽  
Author(s):  
Jaime Figueroa ◽  
Daniela Villagrán ◽  
Carlos Cartes ◽  
Camila Solis ◽  
Guillermo Nourdin‐Galindo ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Proteolytic Enzymes ◽  
Genes Encoding ◽  
Cytotoxic Proteins ◽  
Piscirickettsia Salmonis

scholarly journals Markers for Host-Induced Gene Expression in Trichophyton Dermatophytosis

2005 ◽  
Vol 73 (10) ◽  
pp. 6584-6590 ◽  
Author(s):  
Gil Kaufman ◽  
Israela Berdicevsky ◽  
Judith A. Woodfolk ◽  
Benjamin A. Horwitz
Keyword(s):  
Gene Expression ◽  
Virulence Factors ◽  
Proteolytic Enzymes ◽  
Ex Vivo ◽  
Trichophyton Mentagrophytes ◽  
Skin Tests ◽  
Delayed Type Hypersensitivity ◽  
Protein Substrates ◽  
Genes Encoding ◽  
Encoding Genes

ABSTRACT Dermatophytes are adapted to infect keratinized tissues by their ability to utilize keratin as a nutrient source. Although there have been numerous reports that dermatophytes like Trichophyton sp. secrete proteolytic enzymes, virtually nothing is known about the patterns of gene expression in the host or even when the organisms are cultured on protein substrates in the absence of a host. We characterized the expression of an aminopeptidase gene, the Trichophyton mentagrophytes homolog of the Trichophyton rubrum Tri r 4 gene. The T. rubrum gene was originally isolated based on the ability of the protein encoded by it to induce immediate and delayed-type hypersensitivity in skin tests. T. mentagrophytes Tri m 4 is closely related to Tri r 4 (almost 94% identity at the protein level). Tri m 4 resembles other protease-encoding genes thought to be virulence factors (for example, DPP V of Aspergillus fumigatus). The Tri m 4 protein was detected immunochemically both in fungal extracts and in the culture medium. Expression of the Tri m 4 gene was induced severalfold when T. mentagrophytes was grown on keratin and elastin. Ex vivo, strong induction was observed after culture on blood plasma, but the use of homogenized skin did not result in a significant increase in Tri m 4 transcript levels. In order to identify additional genes encoding putative virulence factors, differential cDNA screening was performed. By this method, a fungal thioredoxin and a cellulase homolog were identified, and both genes were found to be strongly induced by skin extracellular matrix proteins. Induction by superficial (keratin) and deep (elastin) skin elements suggests that the products of these genes may be important in both superficial and deep dermatophytosis, and models for their function are proposed. Upregulation of several newly identified T. mentagrophytes genes on protein substrates suggests that these genes encode proteins which are relevant to the dermatophyte-skin interaction.

scholarly journals Phosphorylation of MgrA and Its Effect on Expression of the NorA and NorB Efflux Pumps of Staphylococcus aureus

2010 ◽  
Vol 192 (10) ◽  
pp. 2525-2534 ◽  
Author(s):  
Que Chi Truong-Bolduc ◽  
David C. Hooper
Keyword(s):  
Staphylococcus Aureus ◽  
Multidrug Resistance ◽  
Virulence Factors ◽  
Double Mutant ◽  
Efflux Pumps ◽  
Efflux Transporters ◽  
Global Regulator ◽  
Binding Assays ◽  
Genes Encoding ◽  
Gel Shift

ABSTRACT MgrA is a global regulator in Staphylococcus aureus that controls the expression of diverse genes encoding virulence factors and multidrug resistance (MDR) efflux transporters. We identified pknB, which encodes the (Ser/Thr) kinase PknB, in the S. aureus genome. PknB was able to autophosphorylate as well as phosphorylate purified MgrA. We demonstrated that rsbU, which encodes a Ser/Thr phosphatase and is involved in the activation of the SigB regulon, was able to dephosphorylate MgrA-P but not PknB-P. Serines 110 and 113 of MgrA were found to be phosphorylated, and Ala substitutions at these positions resulted in reductions in the level of phosphorylation of MgrA. DNA gel shift binding assays using norA and norB promoters showed that MgrA-P was able to bind the norB promoter but not the norA promoter, a pattern which was the reverse of that for unphosphorylated MgrA. The double mutant MgrAS110A-S113A bound to the norA promoter but not the norB promoter. The double mutant led to a 2-fold decrease in norA transcripts and a 2-fold decrease in the MICs of norfloxacin and ciprofloxacin in strain RN6390. Thus, phosphorylation of MgrA results in loss of binding to the norA promoter, but with a gain of the ability to bind the norB promoter. Loss of the ability to phosphorylate MgrA by Ala substitution resulted in increased repression of norA expression and in reductions in susceptibilities to NorA substrates.

scholarly journals Fungal Keratitis in Northern Thailand: Spectrum of Agents, Risk Factors and Putative Virulence Factors

2021 ◽  
Vol 7 (6) ◽  
pp. 475
Author(s):  
Siriporn Chongkae ◽  
Sirida Youngchim ◽  
Joshua D. Nosanchuk ◽  
Angkana Laliam ◽  
Chulaluck Tangmonkongvoragul ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Vision Loss ◽  
Proteolytic Enzymes ◽  
Tertiary Care ◽  
Fungal Keratitis ◽  
High Rate ◽  
Ocular Infection ◽  
Fungal Culture ◽  
Care Hospital ◽  
Northern Thailand

Fungal keratitis (FK) is a serious ocular infection that can result in various degrees of vision loss, including blindness. The aim of the study was to identify and retrospectively review all FK cases diagnosed between August 2012 and December 2020 at a tertiary care hospital in northern Thailand with a specific focus on epidemiologic features, including season, patient sex and age, the spectrum of pathogens, and presence of certain putative virulence factors. Of 1237 patients with corneal ulcers, 294 (23.8%) were confirmed by direct microscopic examination and/or fungal culture. For the positive cases, direct examinations of Calcofluor white (CW) stains and KOH mounts were found in 97.3% (286/294) and 76.5% (225/294), respectively (p < 0.05). Of the cases diagnosed by microscopy and culture, fungi were isolated in 152 (51.7%), with Fusarium spp. being the most frequently identified (n = 69, 45.5%) followed by dematiaceous fungi (n = 45, 29.6%) and Aspergillus spp. (n = 18, 11.8%). The incidence of FK was higher in the rainy season of July to October. The mean age was 54.4 ± 14.4 (SD) years, with a range of 9–88 years. Males (75.8%) were affected significantly more than females (24.2%) (p < 0.05). Of 294 patients, 132 (44.9%) were middle-aged adults (41–60 years) and 107 (36.4%) were older than 60 years. Trauma to the eye by soil or vegetative matter were the most common preceding factors (188/294; 64.0%). We assessed two virulence factors. First, 142 of the 152 culture-positive FK cases were due to molds, indicating that hyphal morphogenesis is extremely important in disease. We also demonstrated that fungal melanization occurs in the molds during the course of FK by applying a melanin-specific monoclonal antibody (MAb) that labeled fungal elements in corneal samples of patients, and melanin particles derived from the hyphae were also recovered after treatment of the samples with proteolytic enzymes, denaturant and hot concentrated acid. In summary, we demonstrate that northern Thailand has a high rate of FK that is influenced by season and males engaged in outside activities are at highest risk for disease. Moulds are significantly more commonly responsible for FK, in part due to their capacity to form hyphae and melanins. Future studies will examine models of fungal corneal interactions and assess additional factors of virulence, such as secreted enzymes, to more deeply decipher the pathogenesis of FK.

Genomic plasticity and antibody response of Bordetella bronchiseptica strain HT200, a natural variant from a thermal spring

2021 ◽  
Vol 368 (6) ◽  
Author(s):  
Jhasketan Badhai ◽  
Subrata K Das
Keyword(s):  
Antibody Response ◽  
Virulence Factors ◽  
Thermal Spring ◽  
Asymptomatic Infection ◽  
Bordetella Bronchiseptica ◽  
Divergent Evolution ◽  
Environmental Niche ◽  
Genomic Plasticity ◽  
Genes Encoding ◽  
Natural Variant

ABSTRACT Classical Bordetella species are primarily isolated from animals and humans causing asymptomatic infection to lethal pneumonia. However, isolation of these bacteria from any extra-host environmental niche has not been reported so far. Here, we have characterized the genomic plasticity and antibody response of Bordetella bronchiseptica strain HT200, isolated from a thermal spring. Genomic ANI value and SNPs-based phylogenetic tree suggest a divergent evolution of strain HT200 from a human-adapted lineage of B. bronchiseptica. Growth and survivability assay showed strain HT200 retained viability for more than 5 weeks in the filter-sterilized spring water. In addition, genes or loci encoding the Bordetella virulence factors such as DNT, ACT and LPS O-antigen were absent in strain HT200, while genes encoding other virulence factors were highly divergent. Phenotypically, strain HT200 was non-hemolytic and showed weak hemagglutination activity, but was able to colonize in the respiratory organs of mice. Further, both infection and vaccination with strain HT200 induced protective antibody response in mouse against challenge infection with virulent B. bronchiseptica strain RB50. In addition, genome of strain HT200 (DSM 26023) showed presence of accessory genes and operons encoding predicted metabolic functions pertinent to the ecological conditions of the thermal spring.

Phenotypic and Molecular Characteristics of Pseudomonas Aeruginosa Isolated from Burn Unit

2021 ◽  
Vol 30 (1) ◽  
pp. 19-28
Author(s):  
Yasser M. Ismail ◽  
Sahar M. Fayed ◽  
Fatma M. Elesawy ◽  
Nora Z Abd El-Halim ◽  
Ola S. El-Shimi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Antimicrobial Susceptibility ◽  
Virulence Gene ◽  
Molecular Characteristics ◽  
Drug Resistant ◽  
Burn Wound ◽  
Burn Wounds ◽  
Related Data ◽  
Genes Encoding

Background: The biggest concern for a burn team is a nosocomial infection in burn patients, which is a significant health issue. Pseudomonas aeruginosa is an extremely troublesome drug-resistant bacterium in the world today. We are now faced with rising P. aeruginosa pan-drug-resistant clones in hospital settings. Objectives: To evaluate the distribution of different virulence factors generated by P. aeruginosa isolated from burn wound infections, together with its antimicrobial susceptibility. Methodology: The isolates reported as P. aeruginosa were further tested for the presence of various phenotypic and genotypic virulence factors including (Biofilm formation, lipase, protease, gelatinase, DNase, bile esculin hydrolysis & hemolysin). Also, genes encoding (nan 1 and Exo A) were investigated by PCR using specific primers. All the isolates were tested for their antimicrobial susceptibility patterns. Results: The study reported that toxins and enzymes were expressed by the tested strains in varying proportions; (92.0%) were producing β-hemolysin, lipase (86%), and protease (86%). The formation of biofilm was observed in 84%. Exo A (70%) was the main virulence gene found in the tested strains. Nan 1 gene was identified in 30% of the samples. 82% of MDRPA isolates were found. There is indeed a relationship between biofilm production and drug resistance, as well as the presence of virulence genes (nan 1 and Exo A) were associated with certain patients and burn wounds characteristics as burn size, burn wound depth, length of hospital stays, and socioeconomic status. Conclusions: Correlation of Pseudomonas aeruginosa virulence profiles with burn wounds and patient-related data can be useful in establishing of an appropriate preventive protocol for hospitalized patients with P. aeruginosa burn serious infections. The targeting of these bacterial virulence arsenals is also a promising approach to developing alternative drugs, which act by attenuating the aggressiveness of the pathogen and reducing its potential to cause vigorous infection.

scholarly journals Occurrence of Genes Encoding Virulence Factors in Bordetella Bronchiseptica Strains Isolated from Infected and Healthy Pigs

2012 ◽  
Vol 56 (4) ◽  
pp. 483-487 ◽  
Author(s):  
Katarzyna Stępniewska ◽  
Iwona Markowska-Daniel
Keyword(s):  
Health Status ◽  
Virulence Factors ◽  
Bordetella Bronchiseptica ◽  
Atrophic Rhinitis ◽  
Genes Encoding ◽  
Progressive Atrophic Rhinitis ◽  
Swine Herds ◽  
Clinical Cases

Abstract The objective of the study was to determine genotypic profiles of Bordetella bronchiseptica (Bbr) strains, based on the occurrence of genes encoding virulence factors, such as flagella (fla), dermonecrotoxin (dnt), and exogenous ferric siderophore receptor (bfrZ), using PCR. 209 tested Bbr strains were obtained from Polish swine herds with different health status (with progressive atrophic rhinitis - PAR, suspected for PAR, and unknown). In total, seven different Bbr genotypes were determined. In 39.2% of Bbr isolates all three genes were present. In 41.1% of the isolates only two genes were detected. The most common genotype dnt+bfrZ-fla+ was present in 60 (28.5%) Bbr strains, 65% of them were obtained from farms with PAR. Twenty five (12%) Bbr isolates were identified as dnt-bfrZ+fla+ genotype and, as above, they were more frequently isolated from clinical cases of disease (84%). Among 31 (14.8%) strains only fla gene was evident, and in nine (4.3%) only dnt gene was present. There were no Bbr strains with bfrZ gene only. These results confirm the heterogenicity among Bbr strains.

scholarly journals A New Rapid and Cost-Effective Method for Detection of Phages, ICEs and Virulence Factors Encoded by Streptococcus pyogenes

2011 ◽  
Vol 60 (3) ◽  
pp. 187-201 ◽  
Author(s):  
ANNA L. BOREK ◽  
JOANNA WILEMSKA ◽  
RADOSŁAW IZDEBSKI ◽  
WALERIA HRYNIEWICZ ◽  
IZABELA SITKIEWICZ
Keyword(s):  
Virulence Factors ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Cost Effective ◽  
Cost Effective Method ◽  
Effective System ◽  
Genes Encoding ◽  
Invasive Infections ◽  
Integration Sites ◽  
Severity Of The Disease

Streptococcus pyogenes (group A Streptococcus, GAS) is a human pathogen that causes diseases of various intensity, from mild strep throat to life threatening invasive infections and postinfectional sequelae. S. pyogenes encodes multiple, often phage encoded, virulence factors and their presence is related to severity of the disease. Acquisition of mobile genetic elements, carrying virulence factors, as phages or ICEs (integrative and cojugative elements) has been shown previously to promote selection of virulent clones. We designed the system of eight low volume multi- and one singleplex PCR reactions to detect genes encoding twenty virulence factors (spd3, sdc, sdaB, sdaD, speB, spyCEP, scpA, mac, sic, speL, K, M, C, I, A, H, G, J, smeZ and ssa) and twenty one phage and ICE integration sites described so far for S. pyogenes. Classification of strains based on the phage and virulence factors absence or presence, correlates with PFGE MLST and emm typing results. We developed a novel, fast and cost effective system that can be used to detect GAS virulence factors. Moreover, this system may become an alternative and effective system to differentiate between GAS strains.

Genes Encoding Proteolytic Enzymes Fungalysin and Subtilisin in Dermatophytes of Human and Animal Origin: A Comparative Study

2019 ◽  
Author(s):  
Engin Kaplan ◽  
Serpil Gonca ◽  
Hazal Kandemir ◽  
Aylin Döğen ◽  
Süleyha Hilmioğlu-Polat ◽  
...  
Keyword(s):  
Comparative Study ◽  
Proteolytic Enzymes ◽  
Animal Origin ◽  
Genes Encoding

scholarly journals MMP20 Hemopexin Domain Mutation in Amelogenesis Imperfecta

2009 ◽  
Vol 89 (1) ◽  
pp. 46-50 ◽  
Author(s):  
S.-K. Lee ◽  
F. Seymen ◽  
H.-Y. Kang ◽  
K.-E. Lee ◽  
K. Gencay ◽  
...  
Keyword(s):  
Mutational Analysis ◽  
Proteolytic Enzymes ◽  
Dental Enamel ◽  
Amelogenesis Imperfecta ◽  
Single Amino Acid ◽  
Functional Protein ◽  
Genes Encoding ◽  
Kallikrein 4 ◽  
Normal Thickness ◽  
Hemopexin Domain

Proteolytic enzymes serve important functions during dental enamel formation, and mutations in the kallikrein 4 ( KLK4) and enamelysin ( MMP20) genes cause autosomal-recessive amelogenesis imperfecta (ARAI). So far, only 1 KLK4 and 3 MMP20 mutations have been reported in ARAI kindreds. To determine whether ARAI in a family with a hypomaturation-type enamel defect is caused by mutations in the genes encoding enamel proteolytic enzymes, we performed mutational analysis on candidate genes. Mutational and haplotype analyses revealed an ARAI-causing point mutation (c.910G>A, p.A304T) in exon 6 of MMP20 that results in a single amino acid substitution in the hemopexin domain. Western blot analysis showed decreased expression of the mutant protein, but zymogram analysis demonstrated that this mutant was a functional protein. The proband and an affected brother were homozygous for the mutation, and both unaffected parents were carriers. The enamel of newly erupted teeth had normal thickness, but was chalky white and became darker with age.

Sign in / Sign up

Export Citation Format

Share Document