scholarly journals The Rhizobacterium Pseudomonas alcaligenes AVO110 Induces the Expression of Biofilm-Related Genes in Response to Rosellinia necatrix Exudates

2021 ◽  
Vol 9 (7) ◽  
pp. 1388
Author(s):  
Adrián Pintado ◽  
Isabel Pérez-Martínez ◽  
Isabel M. Aragón ◽  
José Antonio Gutiérrez-Barranquero ◽  
Antonio de Vicente ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Variable Region ◽  
Phytopathogenic Fungus ◽  
Gene Pools ◽  
Rosellinia Necatrix ◽  
Environmental Isolates ◽  
Pseudomonas Alcaligenes ◽  
Domain Protein ◽  
Genome Analyses ◽  
Soil And Water

The rhizobacterium Pseudomonas alcaligenes AVO110 exhibits antagonism toward the phytopathogenic fungus Rosellinia necatrix. This strain efficiently colonizes R. necatrix hyphae and is able to feed on their exudates. Here, we report the complete genome sequence of P. alcaligenes AVO110. The phylogeny of all available P. alcaligenes genomes separates environmental isolates, including AVO110, from those obtained from infected human blood and oyster tissues, which cluster together with Pseudomonas otitidis. Core and pan-genome analyses showed that P. alcaligenes strains encode highly heterogenic gene pools, with the AVO110 genome encoding the largest and most exclusive variable region (~1.6 Mb, 1795 genes). The AVO110 singletons include a wide repertoire of genes related to biofilm formation, several of which are transcriptionally modulated by R. necatrix exudates. One of these genes (cmpA) encodes a GGDEF/EAL domain protein specific to Pseudomonas spp. strains isolated primarily from the rhizosphere of diverse plants, but also from soil and water samples. We also show that CmpA has a role in biofilm formation and that the integrity of its EAL domain is involved in this function. This study contributes to a better understanding of the niche-specific adaptations and lifestyles of P. alcaligenes, including the mycophagous behavior of strain AVO110.

scholarly journals Diverse Partitiviruses From the Phytopathogenic Fungus, Rosellinia necatrix

2020 ◽  
Vol 11 ◽  
Author(s):  
Paul Telengech ◽  
Sakae Hisano ◽  
Cyrus Mugambi ◽  
Kiwamu Hyodo ◽  
Juan Manuel Arjona-López ◽  
...  
Keyword(s):  
Phytopathogenic Fungus ◽  
Rosellinia Necatrix

scholarly journals Role of Surface Protein SasG in Biofilm Formation by Staphylococcus aureus

2010 ◽  
Vol 192 (21) ◽  
pp. 5663-5673 ◽  
Author(s):  
Joan A. Geoghegan ◽  
Rebecca M. Corrigan ◽  
Dominika T. Gruszka ◽  
Pietro Speziale ◽  
James P. O'Gara ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Surface Protein ◽  
Physiological Concentration ◽  
Peptide Bonds ◽  
Limited Degree ◽  
Accumulation Phase ◽  
Domain Protein

ABSTRACT The SasG surface protein of Staphylococcus aureus has been shown to promote the formation of biofilm. SasG comprises an N-terminal A domain and repeated B domains. Here we demonstrate that SasG is involved in the accumulation phase of biofilm, a process that requires a physiological concentration of Zn2+. The B domains, but not the A domain, are required. Purified recombinant B domain protein can form dimers in vitro in a Zn2+-dependent fashion. Furthermore, the protein can bind to cells that have B domains anchored to their surface and block biofilm formation. The full-length SasG protein exposed on the cell surface is processed within the B domains to a limited degree, resulting in cleaved proteins of various lengths being released into the supernatant. Some of the released molecules associate with the surface-exposed B domains that remain attached to the cell. Studies using inhibitors and mutants failed to identify any protease that could cause the observed cleavage within the B domains. Extensively purified recombinant B domain protein is very labile, and we propose that cleavage occurs spontaneously at labile peptide bonds and that this is necessary for biofilm formation.

The Role of Peganum harmala Ethanolic Extract and Type II Toxin Antitoxin System in Biofilm Formation

Drug Research ◽  
2017 ◽  
Vol 67 (07) ◽  
pp. 385-387
Author(s):  
Nasrin Valizadeh ◽  
Firuzeh Valian ◽  
Nourkhoda Sadeghifard ◽  
Shahriar Karami ◽  
Iraj Pakzad ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Regulatory System ◽  
Ethanolic Extract ◽  
Clinical Isolates ◽  
In Vivo Study ◽  
Type Ii ◽  
Peganum Harmala ◽  
Environmental Isolates

AbstractToxin antitoxin system is a regulatory system that antitoxin inhibits the toxin. We aimed to determine the role of TA loci in biofilm formation in K. pneumoniae clinical and environmental isolates; also inhibition of biofilm formation by Peganum harmala. So, 40 K. pneumoniae clinical and environmental isolates were subjected for PCR to determine the frequency of mazEF, relEB, and mqsRA TA loci. Biofilm formation assay subjected for all isolates. Then, P. harmala was tested against positive biofilm formation strains. Our results demonstrated that relBE TA loci were dominant TA loci; whereas mqsRA TA loci were negative in all isolates. The most environmental isolates showed weak and no biofilm formation while strong and moderate biofilm formation observed in clinical isolates. Biofilm formations by K. pneumoniae in 9 ug/ml concentration were inhibited by P. harmala. In vivo study suggested to be performed to introduce Peganum harmala as anti-biofilm formation in K. pneumoniae.

scholarly journals Phenotypical Comparison of Pseudomonas Aeruginosa Isolated from Human and Veterinary Samples; Impact of Host Adaptation on Infection Pathogenesis

2021 ◽  
Author(s):  
Stefan J. Kaiser ◽  
Annalisa DeRosa ◽  
Christa Ewers ◽  
Frank Günther
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Water Samples ◽  
Biofilm Formation ◽  
Polymorphonuclear Leukocytes ◽  
Environmental Isolates ◽  
Antibiotic Resistant ◽  
Pet Owners ◽  
Zoonotic Risk ◽  
Genetically Determined

Abstract Purpose: Determinants of virulence in Pseudomonas aeruginosa vary strongly depending on its habitat. In this study, we analyzed these alterations depending on the host organism in isolates cultured from canine ears and compared it to clinical extended-spectrum antibiotic-resistant Pseudomonas aeruginosa isolates (XDR), clinical antibiotic-sensitive (non-XDR) from humans and environmental isolates (EI) analyzed during our first study in 2017. Methods: A total of 22 veterinary isolates cultured from canine ears (VET) were examined for spontaneous biofilm formation, stress response in biofilm formation induced by meropenem, in vitro fitness, susceptibility to human serum and polymorphonuclear leukocytes and the genetically determined virulence factors toxA, exoS, exoT, exoU, exoY, nan1, cif, lasA and lasB.Results: We observed significantly elevated spontaneous biofilm formation and serum susceptibility in VET isolates compared to EI and non-XDR isolates as well as significantly decreased in vitro fitness compared to XDR isolates. The VET isolates resembled most the XDR subgroup of isolates previously cultured from blood. Within the environmental isolates, we observed an increase of spontaneous biofilm formation and exoU presence in isolates cultured from community water samples over hospital water samples to pool samples.Conclusions: Considering the distinct differences in some features of the examined VET isolates, a higher degree of phenotypical adaption can be assumed. Increased biofilm formation seems to be a common and characteristic event in isolates adapted to a specific habitat. Therefore amplification of potentially more virulent Pseudomonas aeruginosa strains in domestic animals may lead to elevated zoonotic risk for example for pet owners.

scholarly journals Putative Iron Acquisition Systems in Stenotrophomonas maltophilia

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 2048 ◽  
Author(s):  
V. Kalidasan ◽  
Adleen Azman ◽  
Narcisse Joseph ◽  
Suresh Kumar ◽  
Rukman Awang Hamat ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Stenotrophomonas Maltophilia ◽  
Chemical Nature ◽  
Colorimetric Assay ◽  
Iron Acquisition ◽  
Environmental Isolates ◽  
Iron Starvation ◽  
Receptor System ◽  
Cas Assay ◽  
Significant Expression

Iron has been shown to regulate biofilm formation, oxidative stress response and several pathogenic mechanisms in Stenotrophomonas maltophilia. Thus, the present study is aimed at identifying various iron acquisition systems and iron sources utilized during iron starvation in S. maltophilia. The annotations of the complete genome of strains K279a, R551-3, D457 and JV3 through Rapid Annotations using Subsystems Technology (RAST) revealed two putative subsystems to be involved in iron acquisition: the iron siderophore sensor and receptor system and the heme, hemin uptake and utilization systems/hemin transport system. Screening for these acquisition systems in S. maltophilia showed the presence of all tested functional genes in clinical isolates, but only a few in environmental isolates. NanoString nCounter Elements technology, applied to determine the expression pattern of the genes under iron-depleted condition, showed significant expression for FeSR (6.15-fold), HmuT (12.21-fold), Hup (5.46-fold), ETFb (2.28-fold), TonB (2.03-fold) and Fur (3.30-fold). The isolates, when further screened for the production and chemical nature of siderophores using CAS agar diffusion (CASAD) and Arnows’s colorimetric assay, revealed S. maltophilia to produce catechol-type siderophore. Siderophore production was also tested through liquid CAS assay and was found to be greater in the clinical isolate (30.8%) compared to environmental isolates (4%). Both clinical and environmental isolates utilized hemoglobin, hemin, transferrin and lactoferrin as iron sources. All data put together indicates that S. maltophilia utilizes siderophore-mediated and heme-mediated systems for iron acquisition during iron starvation. These data need to be further confirmed through several knockout studies.

scholarly journals Autotransporters drive biofilm formation and auto-aggregation in the diderm Firmicute Veillonella parvula

2020 ◽  
Author(s):  
Nathalie Béchon ◽  
Alicia Jiménez-Fernández ◽  
Jerzy Witwinowski ◽  
Emilie Bierque ◽  
Najwa Taib ◽  
...  
Keyword(s):  
Dental Plaque ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Targeted Mutagenesis ◽  
Gene Coding ◽  
Domain Protein ◽  
Main Determinants ◽  
Type V ◽  
Functional Analyses

ABSTRACTThe Negativicutes are a clade of Firmicutes that have retained the ancestral diderm character and possess an outer membrane. One of the best studied Negativicute, Veillonella parvula, is an anaerobic commensal and opportunistic pathogen inhabiting complex human microbial communities, including the gut and the dental plaque microbiota. Whereas adhesion and biofilm capacity of V. parvula is expected to be crucial for its maintenance and development in these environments, studies of V. parvula adhesion have been hindered by the lack of efficient genetic tools to perform functional analyses in this bacterium. Here, we took advantage of a recently described naturally transformable V. parvula isolate, SKV38, and adapted tools developed for the closely related Clostridia spp. to perform random transposon and targeted mutagenesis to identify V. parvula genes involved in biofilm formation. We show that type V secreted autotransporters -typically found in diderm bacteria-are the main determinants of V. parvula auto-aggregation and biofilm formation, which compete with each other for binding either to cells or to surfaces, with strong consequences on V. parvula biofilm formation capacity. We also show that inactivation of the gene coding for a poorly characterized metal-dependent phosphohydrolase HD domain protein conserved in the Firmicutes and their closely related diderm phyla inhibits autotransporter-mediated biofilm formation. This study paves the way for further molecular characterization of V. parvula interactions with other bacteria and the host within complex microbiota environments.

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