Control of expression of the RNases J1 and J2 in bacillus subtilis

In Bacillus subtilis, the dual activity 5' exo- and endoribonucleases J1 and J2 are important players in mRNA and stable RNA maturation and degradation. Recent work has improved our understanding of their structure and mechanism of action and identified numerous RNA substrates. However, almost nothing is known about the expression of these enzymes. Here, we have identified the transcriptional and translational signals that control the expression of the rnjA (RNase J1) and rnjB (RNase J2) genes. While the rnjB gene is transcribed constitutively from a sigma A promoter, optimal expression of RNase J1 requires cotranscription and cotranslation with the upstream ykzG gene, encoding a protein of unknown function. In the absence of coupled translation, RNase J1 expression is decreased more than 5-fold. Transcription of the ykzG operon initiates at a sigma A promoter with a noncanonical -35 box that is required for optimal transcription. Biosynthesis of RNase J1 is autocontrolled within a small range (1.4-fold) and also slightly stimulated (1.4-fold) in the absence of RNase J2. These controls are weak but might be useful to maintain the overall RNase J level and possibly also equimolar amounts of the two nucleases in the cell that primarily act as a heterodimer in vivo. © 2014, American Society for Microbiology

The effects of sugars on the biofilm formation of Escherichia coli 185p on stainless steel and polyethylene terephthalate surfaces in a laboratory model

Background: Bacteria utilize various methods in order to live in protection from adverse environmental conditions. One such method involves biofilm formation; however, this formation is dependent on many factors. The type and concentration of substances such as sugars that are present in an environment can be effective facilitators of biofilm formation. Methods: First, the physico-chemical properties of the bacteria and the target surface were studied via the MATS and contact angle measurement methods. Additionally, adhesion to different surfaces in the presence of various concentrations of sugars was compared in order to evaluate the effect of these factors on the biofilm formation of Escherichia coli, which represents a major food contaminant. Results: Results showed that the presence of sugars has no effect on the bacterial growth rate; all three concentrations of sugars were hydrophilic and demonstrated a high affinity toward binding to the surfaces. Conclusions: The impact of sugars and other factors on biofilm formation can vary depending on the type of bacteria present. © 2016, Ahvaz Jundishapur University of Medical Sciences

Frequency evaluation of genes encoding siderophores and the effects of different concentrations of fe ions on growth rate of uropathogenic Escherichia coli

Background and Objectives: Bacteria need iron for growth and most of them can actively acquire Fe ions using especial iron-chelating proteins which named siderophores. We aimed to determine the frequencies of iucA, iroN and irp2 genes in the uropathogenic Escherichia coli (UPEC) isolates. We also analyzed the effects of siderophore genes beside iron supplements on growth rate of the isolates. Materials and Methods: Totally, 170 E. coli strains were isolated from urinary tract infections and the presence of 3 siderophore genes were analyzed using PCR among them. Three final concentrations of 0.1, 0.5 and 1 mMFe(II) and Fe(III) ions were made in M9 broth medium. Inoculated cultures were incubated at 37°C for 33 hours and bacterial density in the suspension was measured with 1 hour intervals using spectrophotometer. Results: The frequency of iucA, iroN and irp2 genes among 170 UPEC isolates were 29 (17.1%), 52 (30.6%) and 116 (68.2%), respectively. In addition, Our findings showed that Fe(II) supplements had significantly higher promoting effects on UPEC growth rate almost in all of the three applied concentrations (0.1, 0.5 and 1 mM) compared to the control group (P<0.0001). Differences between Fe(III) supplemented groups and the controls were statistically significant when 1 mM concentration was added into the medium (p<0.05). Conclusion: irp2 gene probably plays a major role in the pathogenesis of UPEC strains. Promoting or inhibitory effects of iron on bacterial growth mainly depend on the iron concentration in the culture medium however different siderophores have different potentials for capturing and assimilation of Fe ions by the bacteria, especially inside the host cell. © 2016, Tehran University of Medical Science. All rights reserved

Zinc oxide nanoparticle reduced biofilm formation and antigen 43 expressions in uropathogenic Escherichia coli

Objective(s): This study aimed to investigate the effect of zinc oxide nanoparticles (ZnO-np) on biofilm formation and expression of the flu gene in uropathogenic Escherichia coli (UPEC) strains. Materials and Methods: Minimum inhibitory concentration (MIC) of ZnO-np was determined by agar dilution method. The effect of MIC and sub-MIC concentrations of ZnO-np on biofilm formation were determined by microtiter plate assay. The expression level of the flu gene was assessed by Real-Time PCR assay. Results: MIC and sub-MIC ZnO-np concentrations reduced biofilm formation by 50 and 33.4, respectively. Sub-MIC ZnO-np concentration significantly reduced the flu gene expression in the UPEC isolates (P<0.0001). Conclusion: The sub-MIC concentration of ZnO-np reduces biofilm formation and flu gene expression in UPEC isolates. It is suggested to use nanoparticles for coating medical devices to prevent bacterial colonization. © 2017, Mashhad University of Medical Sciences. All rights reserved

Control of expression of the ribonucleases J1 and J2 in B. subtilis

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Effects Of Zno Nanoparticles on Initial Adhesion and fimH Gene Expression Level of Uropathogenic Eschercia coli

Introduction: Uropathogenic Escherichia coli (UPEC) strains are the main causes of urinary tract infections. Adhesion is one of the main and primary steps of UPEC pathogenicity. Type 1 fimbriae is one of the bacterial surface structures that plays an important role in bacterial adhesion. The aim of this study was to evaluate effects of ZnO nanoparticles on the initial adhesion and fimH gene expression level of UPEC. Materials and Method: Four UPEC isolates were used in this study. All isolates were exposed to sub-minimum inhibitory concentration of ZnO nanoparticles (1250 &mu;g/ml). Expression of the fimH gene was evaluated by Real-time PCR. Result: According to the results, presence of nanoparticles reduced the fimH expression level in all four isolates. The highest and lowest rates of down-expression were 1.4-fold and 16.37-fold, respectively. Moreover, these results were consistent with phenotypic observations. Conclusion: However, it is recommended to conduct further studies on gene expression and bacterial adhesion to surfaces to prove whether ZnO nanoparticles could completely prevent UPEC adhesion

Prevalence and expression of PSM A gene in biofilm-producing staphylococcus aureus clinical isolates

Background: Staphylococcus aureus is a frequent cause of hospital and community-associated infections on a global scale. This pathogen is responsible for causing an extensive range of diseases and sometimes create biofilms for their survival. Biofilm formation, leads to difficulty in treatment with antibiotics and antibiotic resistance which is another rising concern in health centers. Some S. aureus virulence factors encode on the core genome, such as alpha-toxin and phenol-soluble modulins (PSMs), which are produced by nearly all strains. Objectives: There is no information about the expression of PSM A gene in clinical isolates of biofilm-producing S. aureus in Iran. This study was performed on clinical samples to determine the prevalence and expression of PSM A gene in biofilm-producing S. aureus clinical isolates. Methods: The clinical sampleswerecollectedandexaminedfor S. aureusby microbiologicalandbiochemical tests. Then, thebiofilm formation in S. aureus isolates was detected by microtiter plate. Finally, the expression of PSM A was determined using SYBR Green real-time PCR. Results: From a total of 60 isolates of S. aureus, 47 strains (78.3) had ability of biofilm formation and the others were negative for biofilm formation. Real-time PCR testing showed that 100 of the strains were positive for biofilms and PSM A genes. The results of phenotypic and genotypic tests of biofilm were closely related to each other and the expression of PSM A gene was 80. It was found that 100 of strains were biofilm producing and PSM A gene was present in 78.3 (47 strains) of them. Conclusions: The prevalence of biofilm production in S. aureus strains isolated from clinical samples was high, so it is highly important to monitor the prevalence of these organisms in hospitals and community as well as their antimicrobial resistance. © 2019, Author(s)

Anti-adhesive effect of ZnO nanoparticles against uropathogenic escherichia coli in bladder epithelial cell cultures and on fimh gene expression

Background: One of the most important causes of urinary tract infection (UTI) in the world is uropathogenic Escherichia coli (UPEC). The first necessary step for establishing UTI is the attachment and invasion of UPEC to the urinary tract epithelial cells. Objectives: In this study, we assessed the anti-adhesion activity of the zinc oxide nanoparticles (ZnO NPs) against UPEC in T24 cell cultures and the effect of these particles on the fimH gene expression by real-time PCR method. Methods: Toxicity of ZnO NPs was measured with MTT test and minimum inhibitory concentration (MIC) was assessed by agar dilution method. Results: Minimum inhibitory concentration for the three UPEC strains that were used in this study were 1250 µg.mL-1 . Our results showed that the IC50 of ZnO NPs for the T24-cells was 19.53 µg.mL-1 and 0.3 µg.mL-1 is a nontoxic concentration for this cell line. These low concentrations of ZnO suspensions showed 28.77 to 44.71 decrease in the attachment of UPEC to the T24 cells and also could decrease the expression of fimH gene in UPEC. Conclusions: This study showed the anti-adhesive effect of ZnO suspension against UPEC adhesion to the T24 cells and decreased fimH gene expression are seen in these low concentrations of ZnO suspensions. © 2019, Author(s)

Tracking the elusive 5′ exonuclease activity of Chlamydomonas reinhardtii RNase J

Key message: Chlamydomonas RNase J is the first member of this enzyme family that has endo- but no intrinsic 5′ exoribonucleolytic activity. This questions its proposed role in chloroplast mRNA maturation. Abstract: RNA maturation and stability in the chloroplast are controlled by nuclear-encoded ribonucleases and RNA binding proteins. Notably, mRNA 5′ end maturation is thought to be achieved by the combined action of a 5′ exoribonuclease and specific pentatricopeptide repeat proteins (PPR) that block the progression of the nuclease. In Arabidopsis the 5′ exo- and endoribonuclease RNase J has been implicated in this process. Here, we verified the chloroplast localization of the orthologous Chlamydomonas (Cr) RNase J and studied its activity, both in vitro and in vivo in a heterologous B. subtilis system. Our data show that Cr RNase J has endo- but no significant intrinsic 5′ exonuclease activity that would be compatible with its proposed role in mRNA maturation. This is the first example of an RNase J ortholog that does not possess a 5′ exonuclease activity. A yeast two-hybrid screen revealed a number of potential interaction partners but three of the most promising candidates tested, failed to induce the latent exonuclease activity of Cr RNase J. We still favor the hypothesis that Cr RNase J plays an important role in RNA metabolism, but our findings suggest that it rather acts as an endoribonuclease in the chloroplast. © 2018 Springer Science+Business Media B.V., part of Springer Natur