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.

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 Membrane Lipid Composition of the Moderately Thermophilic Ammonia-Oxidizing Archaeon “Candidatus Nitrosotenuis uzonensis” at Different Growth Temperatures

2019 ◽  
Vol 85 (20) ◽  
Author(s):  
Nicole J. Bale ◽  
Marton Palatinszky ◽  
W. Irene C. Rijpstra ◽  
Craig W. Herbold ◽  
Michael Wagner ◽  
...  
Keyword(s):  
Lipid Composition ◽  
Strong Influence ◽  
Thermal Spring ◽  
Membrane Lipid ◽  
Effect Of Temperature ◽  
Environmental Niche ◽  
Membrane Lipid Composition ◽  
Moderately Thermophilic ◽  
Wide Range ◽  
Membrane Spanning

ABSTRACT “Candidatus Nitrosotenuis uzonensis” is the only cultured moderately thermophilic member of the thaumarchaeotal order Nitrosopumilales (NP) that contains many mesophilic marine strains. We examined its membrane lipid composition at different growth temperatures (37°C, 46°C, and 50°C). Its lipids were all membrane-spanning glycerol dialkyl glycerol tetraethers (GDGTs), with 0 to 4 cyclopentane moieties. Crenarchaeol (cren), the characteristic thaumarchaeotal GDGT, and its isomer (crenʹ) were present in high abundance (30 to 70%). The GDGT polar headgroups were mono-, di-, and trihexoses and hexose/phosphohexose. The ratio of glycolipid to phospholipid GDGTs was highest in the cultures grown at 50°C. With increasing growth temperatures, the relative contributions of cren and crenʹ increased, while those of GDGT-0 to GDGT-4 (including isomers) decreased. TEX86 (tetraether index of tetraethers consisting of 86 carbons)-derived temperatures were much lower than the actual growth temperatures, further demonstrating that TEX86 does not accurately reflect the membrane lipid adaptation of thermophilic Thaumarchaeota. As the temperature increased, specific GDGTs changed relative to their isomers, possibly representing temperature adaption-induced changes in cyclopentane ring stereochemistry. Comparison of a wide range of thaumarchaeotal core lipid compositions revealed that the “Ca. Nitrosotenuis uzonensis” cultures clustered separately from other members of the NP order and the Nitrososphaerales (NS) order. While phylogeny generally seems to have a strong influence on GDGT distribution, our analysis of “Ca. Nitrosotenuis uzonensis” demonstrates that its terrestrial, higher-temperature niche has led to a lipid composition that clearly differentiates it from other NP members and that this difference is mostly driven by its high crenʹ content. IMPORTANCE For Thaumarchaeota, the ratio of their glycerol dialkyl glycerol tetraether (GDGT) lipids depends on growth temperature, a premise that forms the basis of the widely applied TEX86 paleotemperature proxy. A thorough understanding of which GDGTs are produced by which Thaumarchaeota and what the effect of temperature is on their GDGT composition is essential for constraining the TEX86 proxy. “Ca. Nitrosotenuis uzonensis” is a moderately thermophilic thaumarchaeote enriched from a thermal spring, setting it apart in its environmental niche from the other marine mesophilic members of its order. Indeed, we found that the GDGT composition of “Ca. Nitrosotenuis uzonensis” cultures was distinct from those of other members of its order and was more similar to those of other thermophilic, terrestrial Thaumarchaeota. This suggests that while phylogeny has a strong influence on GDGT distribution, the environmental niche that a thaumarchaeote inhabits also shapes its GDGT composition.

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 Analysis of Immunity to Febrile Malaria in Children That Distinguishes Immunity from Lack of Exposure

2009 ◽  
Vol 77 (5) ◽  
pp. 1917-1923 ◽  
Author(s):  
Philip Bejon ◽  
George Warimwe ◽  
Claire L. Mackintosh ◽  
Margaret J. Mackinnon ◽  
Sam M. Kinyanjui ◽  
...  
Keyword(s):  
Cell Surface ◽  
Antibody Response ◽  
Observational Studies ◽  
Asymptomatic Infection ◽  
Bed Nets ◽  
Bed Net ◽  
Red Cell ◽  
Vaccine Trials ◽  
Net Use ◽  
Malaria Episodes

ABSTRACT In studies of immunity to malaria, the absence of febrile malaria is commonly considered evidence of “protection.” However, apparent “protection” may be due to a lack of exposure to infective mosquito bites or due to immunity. We studied a cohort that was given curative antimalarials before monitoring began and documented newly acquired asymptomatic parasitemia and febrile malaria episodes during 3 months of surveillance. With increasing age, there was a shift away from febrile malaria to acquiring asymptomatic parasitemia, with no change in the overall incidence of infection. Antibodies to the infected red cell surface were associated with acquiring asymptomatic infection rather than febrile malaria or remaining uninfected. Bed net use was associated with remaining uninfected rather than acquiring asymptomatic infection or febrile malaria. These observations suggest that most uninfected children were unexposed rather than “immune.” Had they been immune, we would have expected the proportion of uninfected children to rise with age and that the uninfected children would have been distinguished from children with febrile malaria by the protective antibody response. We show that removing the less exposed children from conventional analyses clarifies the effects of immunity, transmission intensity, bed nets, and age. Observational studies and vaccine trials will have increased power if they differentiate between unexposed and immune children.

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 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.

scholarly journals Tripartite holobiont system in a vent snail broadens the concept of chemosymbiosis

2020 ◽  
Author(s):  
Yi Yang ◽  
Jin Sun ◽  
Chong Chen ◽  
Yadong Zhou ◽  
Yi Lan ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Deep Sea ◽  
Extreme Environments ◽  
Host Immunity ◽  
Energy Sources ◽  
High Quality ◽  
Genomic Plasticity ◽  
Changing Environments ◽  
Metabolic Heterogeneity ◽  
Genomic Basis

AbstractMany animals inhabiting deep-sea vents are energetically dependent on chemosynthetic endosymbionts, but how such symbiont community interacts with host, and whether other nutritional sources are available to such animals remain unclear. To reveal the genomic basis of symbiosis in the vent snail Alviniconcha marisindica, we sequenced high-quality genomes of the host and gill campylobacterial endosymbionts, as well as metagenome of the gut microbiome. The gill endosymbiont has a streamlined genome for efficient chemoautotrophy, but also shows metabolic heterogeneity among populations. Inter- and intra-host variabilities among endosymbiont populations indicate the host poses low selection on gill endosymbionts. Virulence factors and genomic plasticity of the endosymbiont provide advantages for cooperating with host immunity to maintain mutualism and thriving in changing environments. In addition to endosymbiosis, the gut and its microbiome expand the holobiont’s utilisation of energy sources. Host-microbiota mutualism contributes to a highly flexible holobiont that can excel in various extreme environments.

scholarly journals Accelerated evolution and diversifying selection drove the adaptation of cetacean bone microstructure

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Di Sun ◽  
Xuming Zhou ◽  
Zhenpeng Yu ◽  
Shixia Xu ◽  
Inge Seim ◽  
...  
Keyword(s):  
Bone Development ◽  
Bone Microstructure ◽  
Divergent Evolution ◽  
Behavioral Adaptations ◽  
Accelerated Evolution ◽  
Genes Encoding ◽  
Show Evidence ◽  
Evolutionary Event ◽  
Osteoclast Function ◽  
Specialized Structure

Abstract Background The transition from land to sea by the ancestor of cetaceans approximately 50 million years ago was an incredible evolutionary event that led to a series of morphological, physiological, and behavioral adaptations. During this transition, bone microstructure evolved from the typical terrestrial form to the specialized structure found in modern cetaceans. While the bone microstructure of mammals has been documented before, investigations of its genetic basis lag behind. The increasing number of cetaceans with whole-genome sequences available may shed light on the mechanism underlying bone microstructure evolution as a result of land to water transitions. Results Cetacean bone microstructure is consistent with their diverse ecological behaviors. Molecular evolution was assessed by correlating bone microstructure and gene substitution rates in terrestrial and aquatic species, and by detecting genes under positive selection along ancestral branches of cetaceans. We found that: 1) Genes involved in osteoclast function are under accelerated evolution in cetaceans, suggestive of important roles in bone remodeling during the adaptation to an aquatic environment; 2) Genes in the Wnt pathway critical for bone development and homeostasis show evidence of divergent evolution in cetaceans; 3) Several genes encoding bone collagens are under selective pressure in cetaceans. Conclusions Our results suggest that evolutionary pressures have shaped the bone microstructure of cetaceans, to facilitate life in diverse aquatic environments.

scholarly journals Co-existence of virulence factors and antibiotic resistance in new Klebsiella pneumoniae clones emerging in south of Italy

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Teresa Fasciana ◽  
Bernardina Gentile ◽  
Maria Aquilina ◽  
Andrea Ciammaruconi ◽  
Chiara Mascarella ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Klebsiella Pneumoniae ◽  
Virulence Factors ◽  
In Silico ◽  
Geographical Area ◽  
In Silico Analysis ◽  
University Hospital ◽  
Uptake System ◽  
Genes Encoding ◽  
Silico Analysis

Abstract Background Endemic presence of Klebsiella pneumoniae resistant to carbapenem in Italy has been due principally to the clonal expansion of CC258 isolates; however, recent studies suggest an ongoing epidemiological change in this geographical area. Methods 50 K. pneumoniae strains, 25 carbapenem-resistant (CR-Kp) and 25 susceptible (CS-Kp), collected from march 2014 to march 2016 at the Laboratory of Bacteriology of the Paolo Giaccone Polyclinic University hospital of Palermo, Italy, were characterized for antibiotic susceptibility and fully sequenced by next generation sequencing (NGS) for the in silico analysis of resistome, virulome, multi-locus sequence typing (MLST) and core single nucleotide polymorphism (SNP) genotypes Results MLST in silico analysis of CR-Kp showed that 52% of isolates belonged to CC258, followed by ST395 (12%), ST307 (12%), ST392 (8%), ST348 (8%), ST405 (4%) and ST101 (4%). In the CS-Kp group, the most represented isolate was ST405 (20%), followed by ST392 and ST15 (12%), ST395, ST307 and ST1727 (8%). The in silico β-lactamase analysis of the CR-Kp group showed that the most detected gene was blaSHV (100%), followed by blaTEM (92%), blaKPC (88%), blaOXA (88%) and blaCTX-M (32%). The virulome analysis detected mrk operon in all studied isolates, and wzi-2 was found in three CR-Kp isolates (12%). Furthermore, the distribution of virulence genes encoding for the yersiniabactin system, its receptor fyuA and the aerobactin system did not show significant distribution differences between CR-Kp and CS-Kp, whereas the Klebsiella ferrous iron uptake system (kfuA, kfuB and kfuC genes), the two-component system kvgAS and the microcin E495 were significantly (p < 0.05) prevalent in the CS-Kp group compared to the CR-Kp group. Core SNP genotyping, correlating with the MLST data, allowed greater strain tracking and discrimination than MLST analysis. Conclusions Our data support the idea that an epidemiological change is ongoing in the Palermo area (Sicily, Italy). In addition, our analysis revealed the co-existence of antibiotic resistance and virulence factors in CR-Kp isolates; this characteristic should be considered for future genomic surveillance studies.

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