scholarly journals Genetic Analysis of the AdnA Regulon in Pseudomonas fluorescens: Nonessential Role of Flagella in Adhesion to Sand and Biofilm Formation

2003 ◽  
Vol 185 (2) ◽  
pp. 453-460 ◽  
Author(s):  
Eduardo A. Robleto ◽  
Inmaculada López-Hernández ◽  
Mark W. Silby ◽  
Stuart B. Levy
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Transcription Factor ◽  
Pseudomonas Fluorescens ◽  
Biofilm Formation ◽  
Deletion Mutant ◽  
Open Reading Frames ◽  
Cell Processes ◽  
Reading Frames ◽  
Insertion Mutants

ABSTRACT AdnA is a transcription factor in Pseudomonas fluorescens that affects flagellar synthesis, biofilm formation, and sand adhesion. To identify the AdnA regulon, we used a promoterless Tn5-lacZ element to study the phenotypes of insertion mutants in the presence and absence of AdnA. Of 12,000 insertions, we identified seven different putative open reading frames (ORFs) activated by AdnA (named aba for activated by AdnA). aba120 and aba177 showed homology to flgC and flgI, components of the basal body of the flagella in Pseudomonas aeruginosa. Two other insertions, aba18 and aba51, disrupted genes affecting chemotaxis. The mutant loci aba160 (possibly affecting lipopolysaccharide synthesis) and aba175 (unknown function) led to loss of flagella. The mutant bearing aba203 became motile when complemented with adnA, but the mutated gene showed no similarity to known genes. Curiously, aba18, aba51, aba160, and aba203 mutants formed biofilms even in the absence of AdnA, suppressing the phenotype of the adnA deletion mutant. The combined findings suggest that flagella are nonessential for sand attachment or biofilm formation. Sequence and promoter analyses indicate that AdnA affects at least 23 ORFs either directly or by polar effects. These results support the concept that AdnA regulates cell processes other than those directly related to flagellar synthesis and define a broader cadre of genes in P. fluorescens than that described so far for its homolog, FleQ, in P. aeruginosa.

Elastase LasB of Pseudomonas aeruginosa promotes biofilm formation partly through rhamnolipid-mediated regulation

2014 ◽  
Vol 60 (4) ◽  
pp. 227-235 ◽  
Author(s):  
Hua Yu ◽  
Xiaomei He ◽  
Wei Xie ◽  
Junzhi Xiong ◽  
Halei Sheng ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Deletion Mutant ◽  
Gene Expression Analysis ◽  
Bacterial Attachment ◽  
Transcriptional Level ◽  
Complementary Strain ◽  
Host Infection ◽  
The Impact

Elastase LasB, an important extracellular virulence factor, is shown to play an important role in the pathogenicity of Pseudomonas aeruginosa during host infection. However, the role of LasB in the life cycle of P. aeruginosa is not completely understood. This report focuses on the impact of LasB on biofilm formation of P. aeruginosa PAO1. Here, we reported that the lasB deletion mutant (ΔlasB) displayed significantly decreased bacterial attachment, microcolony formation, and extracellular matrix linkage in biofilm associated with decreased biosynthesis of rhamnolipids compared with PAO1 and lasB complementary strain (ΔlasB+). Nevertheless, the ΔlasB developed restored biofilm formation with supplementation of exogenous rhamnolipids. Further gene expression analysis revealed that the mutant of lasB could result in the downregulation of rhamnolipid synthesis at the transcriptional level. Taken together, these results indicated that LasB could promote biofilm formation partly through the rhamnolipid-mediated regulation.

scholarly journals HbxB Is a Key Regulator for Stress Response and β-Glucan Biogenesis in Aspergillus nidulans

2021 ◽  
Vol 9 (1) ◽  
pp. 144
Author(s):  
Sung-Hun Son ◽  
Mi-Kyung Lee ◽  
Ye-Eun Son ◽  
Hee-Soo Park
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Aspergillus Nidulans ◽  
Deletion Mutant ◽  
Phenotypic Analysis ◽  
Spore Viability ◽  
Fungal Development ◽  
Expression Of Genes ◽  
Trehalose Biosynthesis

Homeobox transcription factors are conserved in eukaryotes and act as multi-functional transcription factors in filamentous fungi. Previously, it was demonstrated that HbxB governs fungal development and spore viability in Aspergillus nidulans. Here, the role of HbxB in A. nidulans was further characterized. RNA-sequencing revealed that HbxB affects the transcriptomic levels of genes associated with trehalose biosynthesis and response to thermal, oxidative, and radiation stresses in asexual spores called conidia. A phenotypic analysis found that hbxB deletion mutant conidia were more sensitive to ultraviolet stress. The loss of hbxB increased the mRNA expression of genes associated with β-glucan degradation and decreased the amount of β-glucan in conidia. In addition, hbxB deletion affected the expression of the sterigmatocystin gene cluster and the amount of sterigmatocystin. Overall, these results indicated that HbxB is a key transcription factor regulating trehalose biosynthesis, stress tolerance, β-glucan degradation, and sterigmatocystin production in A.nidulans conidia.

scholarly journals Structural and Functional Analysis of the Phosphonoacetate Hydrolase (phnA) Gene Region in Pseudomonas fluorescens 23F

2001 ◽  
Vol 183 (11) ◽  
pp. 3268-3275 ◽  
Author(s):  
Anna N. Kulakova ◽  
Leonid A. Kulakov ◽  
Natalya V. Akulenko ◽  
Vladimir N. Ksenzenko ◽  
John T. G. Hamilton ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Bond Cleavage ◽  
Transcriptional Regulators ◽  
Open Reading Frames ◽  
Cell Analysis ◽  
Rna Analysis ◽  
Cleavage Enzyme ◽  
Reading Frames ◽  
Lysr Family ◽  
In Cells

ABSTRACT The Pseudomonas fluorescens 23F phosphonoacetate hydrolase gene (phnA) encodes a novel carbon-phosphorus bond cleavage enzyme whose expression is independent of the phosphate status of the cell. Analysis of the regions adjacent to the phosphonoacetate hydrolase structural gene (phnA) indicated the presence of five open reading frames (ORFs). These include one (phnR) whose putative product shows high levels of homology to the LysR family of positive transcriptional regulators. Its presence was shown to be necessary for induction of the hydrolase activity. 2-Phosphonopropionate was found to be an inducer (and poor substrate) for phosphonoacetate hydrolase. Unlike phosphonoacetate, which is also an inducer of phosphonoacetate hydrolase, entry of 2-phosphonopropionate into cells appeared to be dependent on the presence of a gene (phnB) that lies immediately downstream of phnA and whose putative product shows homology to the glycerol-3-phosphate transporter. RNA analysis revealed transcripts for the phnAB andphnR operons, which are transcribed divergently; the resulting mRNAs overlapped by 29 nucleotide bases at their 5′ ends. Transcripts of phnAB were detected only in cells grown in the presence of phosphonoacetate, whereas transcripts ofphnR were observed in cells grown under both induced and uninduced conditions. The expression of three additional genes found in the phnA region did not appear necessary for the degradation of phosphonoacetate and 2-phosphonopropionate by eitherPseudomonas putida or Escherichia colicells.

scholarly journals PmtA Regulates Pyocyanin Expression and Biofilm Formation in Pseudomonas aeruginosa

2021 ◽  
Vol 12 ◽  
Author(s):  
Amy V. Thees ◽  
Kathryn M. Pietrosimone ◽  
Clare K. Melchiorre ◽  
Jeremiah N. Marden ◽  
Joerg Graf ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Metal Binding ◽  
Biofilm Formation ◽  
Binding Capacity ◽  
Opportunistic Pathogen ◽  
Small Molecular Weight ◽  
Heavy Metal Binding ◽  
The Impact

The opportunistic pathogen Pseudomonas aeruginosa expresses a small molecular weight, cysteine-rich protein (PmtA), identified as a metallothionein (MT) protein family member. The MT family proteins have been well-characterized in eukaryotes as essential for zinc and copper homeostasis, protection against oxidative stress, and the ability to modify a variety of immune activities. Bacterial MTs share sequence homology, antioxidant chemistry, and heavy metal-binding capacity with eukaryotic MTs, however, the impact of bacterial MTs on virulence and infection have not been well-studied. In the present study, we investigated the role of PmtA in P. aeruginosa PAO1 using a PmtA-deficient strain (ΔpmtA). Here we demonstrated the virulence factor, pyocyanin, relies on the expression of PmtA. We showed that PmtA may be protective against oxidative stress, as an alternative antioxidant, glutathione, can rescue pyocyanin expression. Furthermore, the expression of phzM, which encodes a pyocyanin precursor enzyme, was decreased in the ΔpmtA mutant during early stationary phase. Upregulated pmtA expression was previously detected in confluent biofilms, which are essential for chronic infection, and we observed that the ΔpmtA mutant was disrupted for biofilm formation. As biofilms also modulate antibiotic susceptibility, we examined the ΔpmtA mutant susceptibility to antibiotics and found that the ΔpmtA mutant is more susceptible to cefepime and ciprofloxacin than the wild-type strain. Finally, we observed that the deletion of pmtA results in decreased virulence in a waxworm model. Taken together, our results support the conclusion that PmtA is necessary for the full virulence of P. aeruginosa and may represent a potential target for therapeutic intervention.

scholarly journals DNA Microarray Analysis of Central Carbohydrate Metabolism: Glycolytic/Gluconeogenic Carbon Switch in the Hyperthermophilic Crenarchaeum Thermoproteus tenax

2008 ◽  
Vol 190 (6) ◽  
pp. 2231-2238 ◽  
Author(s):  
Melanie Zaparty ◽  
Alexander Zaigler ◽  
Claudia Stamme ◽  
Jörg Soppa ◽  
Reinhard Hensel ◽  
...  
Keyword(s):  
Carbohydrate Metabolism ◽  
Dna Microarray ◽  
Transcript Level ◽  
Open Reading Frames ◽  
Transcriptional Analysis ◽  
Heterotrophic Growth ◽  
Thermoproteus Tenax ◽  
Central Carbohydrate Metabolism ◽  
Reading Frames

ABSTRACT In order to unravel the role of regulation on transcript level in central carbohydrate metabolism (CCM) of Thermoproteus tenax, a focused DNA microarray was constructed by using 85 open reading frames involved in CCM. A transcriptional analysis comparing heterotrophic growth on glucose versus autotrophic growth on CO2-H2 was performed.

Assessment of pelA-carried Pseudomonas aeruginosa isolates in respect to biofilm formation

2019 ◽  
pp. 1180-1187
Author(s):  
Mahmood Abd AL- Razzaq Hassan AL-Sheikhly ◽  
Laith N. Musleh ◽  
Harith J. F. Al-Mathkhury
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Nosocomial Infections ◽  
Biofilm Formation ◽  
Clinical Samples ◽  
Antibacterial Resistance ◽  
Gentamicin Resistance ◽  
Pcr Method

Owing to high antibacterial resistance of Pseudomonas aeruginosa, it could be considered as the main reason behind the nosocomial infections. P. aeruginosa has a well-known biofilm forming ability. The expression of polysaccharide encoding locus (pelA gene) by P. aeruginosa is essential for this ability. The purpose of the current research was to determine the biofilm formation in P. aeruginosa isolated from clinical samples and to evaluate the role of the selected PelA gene in biofilm formation using PCR method in Iraqi patients. Results revealed that 24 (96%) isolates were found to have the ability to form biofilm that was remarkably related to gentamicin resistance. Moreover, the pelA gene was found in all biofilm-producers. In conclusion, the results of the current study revealed that the P. aeruginosa biofilm-producer isolates were resistant to the antibiotics in question. Likewise, because of wide spreading, it appears that the pelA gene is related to biofilm formation.

scholarly journals Complete Genome Sequences of Pseudomonas aeruginosa Phages vB_PaeP_PcyII-10_P3P1 and vB_PaeM_PcyII-10_PII10A

2016 ◽  
Vol 4 (6) ◽  
Author(s):  
Christine Pourcel ◽  
Cédric Midoux ◽  
Libera Latino ◽  
Marie-Agnès Petit ◽  
Gilles Vergnaud
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Complete Genome ◽  
Open Reading Frames ◽  
Genome Sequences ◽  
Reading Frames

vB_PaeP_PcyII-10_P3P1 and vB_PaeM_PcyII-10_PII10A are Pseudomonas aeruginosa bacteriophages belonging, respectively, to the Lit1virus genus of the Podoviridae family and the Pbunavirus genus of the Myoviridae family. Their genomes are 72,778 bp and 65,712 bp long, containing 94 and 93 predicted open reading frames, respectively.

scholarly journals Sequence of the Genome of the Temperate, Serotype-Converting,Pseudomonas aeruginosa Bacteriophage D3

2000 ◽  
Vol 182 (21) ◽  
pp. 6066-6074 ◽  
Author(s):  
Andrew M. Kropinski
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Sequence Similarity ◽  
Complete Sequence ◽  
Open Reading Frames ◽  
Gene Encoding ◽  
Virus Family ◽  
Double Stranded Dna ◽  
High Degree ◽  
Phage Proteins ◽  
Reading Frames

ABSTRACT Temperate bacteriophage D3, a member of the virus familySiphoviridae, is responsible for serotype conversion in its host, Pseudomonas aeruginosa. The complete sequence of the double-stranded DNA genome has been determined. The 56,426 bp contains 90 putative open reading frames (ORFs) and four genes specifying tRNAs. The latter are specific for methionine (AUG), glycine (GGA), asparagine (AAC), and threonine (ACA). The tRNAs may function in the translation of certain highly expressed proteins from this relatively AT-rich genome. D3 proteins which exhibited a high degree of sequence similarity to previously characterized phage proteins included the portal, major head, tail, and tail tape measure proteins, endolysin, integrase, helicase, and NinG. The layout of genes was reminiscent of lambdoid phages, with the exception of the placement of the endolysin gene, which parenthetically also lacked a cognate holin. The greatest sequence similarity was found in the morphogenesis genes to coliphages HK022 and HK97. Among the ORFs was discovered the gene encoding the fucosamine O-acetylase, which is in part responsible for the serotype conversion events.

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