scholarly journals Ribosome Reconstruction during Recovery from High-Hydrostatic-Pressure-Induced Injury in Bacillus subtilis

2019 ◽  
Vol 86 (1) ◽  
Author(s):  
Huyen Thi Minh Nguyen ◽  
Genki Akanuma ◽  
Tu Thi Minh Hoa ◽  
Yuji Nakai ◽  
Keitarou Kimura ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Growth Arrest ◽  
Recovery Process ◽  
Dependent Manner ◽  
Bacterial Cells ◽  
Vegetative Cells ◽  
Content Type ◽  
Growth Recovery

ABSTRACT Vegetative cells of Bacillus subtilis can recover from injury after high-hydrostatic-pressure (HHP) treatment at 250 MPa. DNA microarray analysis revealed that substantial numbers of ribosomal genes and translation-related genes (e.g., translation initiation factors) were upregulated during the growth arrest phase after HHP treatment. The transcript levels of cold shock-responsive genes, whose products play key roles in efficient translation, and heat shock-responsive genes, whose products mediate correct protein folding or degrade misfolded proteins, were also upregulated. In contrast, the transcript level of hpf, whose product (Hpf) is involved in ribosome inactivation through the dimerization of 70S ribosomes, was downregulated during the growth arrest phase. Sucrose density gradient sedimentation analysis revealed that ribosomes were dissociated in a pressure-dependent manner and then reconstructed. We also found that cell growth after HHP-induced injury was apparently inhibited by the addition of Mn2+ or Zn2+ to the recovery medium. Ribosome reconstruction in the HHP-injured cells was also significantly delayed in the presence of Mn2+ or Zn2+. Moreover, Zn2+, but not Mn2+, promoted dimer formation of 70S ribosomes in the HHP-injured cells. Disruption of the hpf gene suppressed the Zn2+-dependent accumulation of ribosome dimers, partially relieving the inhibitory effect of Zn2+ on the growth recovery of HHP-treated cells. In contrast, it was likely that Mn2+ prevented ribosome reconstruction without stimulating ribosome dimerization. Our results suggested that both Mn2+ and Zn2+ can prevent ribosome reconstruction, thereby delaying the growth recovery of HHP-injured B. subtilis cells. IMPORTANCE HHP treatment is used as a nonthermal processing technology in the food industry to inactivate bacteria while retaining high quality of foods under suppressed chemical reactions. However, some populations of bacterial cells may survive the inactivation. Although the survivors are in a transient nongrowing state due to HHP-induced injury, they can recover from the injury and then start growing, depending on the postprocessing conditions. The recovery process in terms of cellular components after the injury remains unclear. Transcriptome analysis using vegetative cells of Bacillus subtilis revealed that the translational machinery can preferentially be reconstructed after HHP treatment. We found that both Mn2+ and Zn2+ prolonged the growth-arrested stage of HHP-injured cells by delaying ribosome reconstruction. It is likely that ribosome reconstruction is crucial for the recovery of growth ability in HHP-injured cells. This study provides further understanding of the recovery process in HHP-injured B. subtilis cells.

scholarly journals Transcriptional Regulation and Mechanism of SigN (ZpdN), a pBS32-Encoded Sigma Factor in Bacillus subtilis

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Aisha T. Burton ◽  
Aaron DeLoughery ◽  
Gene-Wei Li ◽  
Daniel B. Kearns
Keyword(s):  
Dna Damage ◽  
Bacillus Subtilis ◽  
Sigma Factor ◽  
Consensus Sequence ◽  
Sigma Factors ◽  
Sequencing Analysis ◽  
Dependent Manner ◽  
Content Type ◽  
Alternative Sigma Factors ◽  
Bona Fide

ABSTRACT Laboratory strains of Bacillus subtilis encode many alternative sigma factors, each dedicated to expressing a unique regulon such as those involved in stress resistance, sporulation, and motility. The ancestral strain of B. subtilis also encodes an additional sigma factor homolog, ZpdN, not found in lab strains due to being encoded on the large, low-copy-number plasmid pBS32, which was lost during domestication. DNA damage triggers pBS32 hyperreplication and cell death in a manner that depends on ZpdN, but how ZpdN mediates these effects is unknown. Here, we show that ZpdN is a bona fide sigma factor that can direct RNA polymerase to transcribe ZpdN-dependent genes, and we rename ZpdN SigN accordingly. Rend-seq (end-enriched transcriptome sequencing) analysis was used to determine the SigN regulon on pBS32, and the 5′ ends of transcripts were used to predict the SigN consensus sequence. Finally, we characterize the regulation of SigN itself and show that it is transcribed by at least three promoters: PsigN1, a strong SigA-dependent LexA-repressed promoter; PsigN2, a weak SigA-dependent constitutive promoter; and PsigN3, a SigN-dependent promoter. Thus, in response to DNA damage SigN is derepressed and then experiences positive feedback. How cells die in a pBS32-dependent manner remains unknown, but we predict that death is the product of expressing one or more genes in the SigN regulon. IMPORTANCE Sigma factors are utilized by bacteria to control and regulate gene expression. Some sigma factors are activated during times of stress to ensure the survival of the bacterium. Here, we report the presence of a sigma factor that is encoded on a plasmid that leads to cellular death after DNA damage.

scholarly journals Characterization of high hydrostatic pressure-injured Bacillus subtilis cells

2017 ◽  
Vol 81 (6) ◽  
pp. 1235-1240 ◽  
Author(s):  
Takashi Inaoka ◽  
Keitarou Kimura ◽  
Kazuya Morimatsu ◽  
Kazutaka Yamamoto
Keyword(s):  
Bacillus Subtilis ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure

scholarly journals In VitroEffects of Polyphosphate against Prevotella intermedia in Planktonic Phase and Biofilm

2015 ◽  
Vol 60 (2) ◽  
pp. 818-826 ◽  
Author(s):  
Eun-Young Jang ◽  
Minjung Kim ◽  
Mi Hee Noh ◽  
Ji-Hoi Moon ◽  
Jin-Yong Lee
Keyword(s):  
Biofilm Formation ◽  
Sodium Tripolyphosphate ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Prevotella Intermedia ◽  
Dependent Manner ◽  
Bacterial Cells ◽  
Concentration Dependent Manner ◽  
Content Type ◽  
Planktonic Phase

ABSTRACTPolyphosphate (polyP) has gained a wide interest in the food industry due to its potential as a decontaminating agent. In this study, we examined the effect of sodium tripolyphosphate (polyP3; Na5P3O10) against planktonic and biofilm cells ofPrevotella intermedia, a major oral pathogen. The MIC of polyP3 againstP. intermediaATCC 49046 determined by agar dilution method was 0.075%, while 0.05% polyP3 was bactericidal againstP. intermediain time-kill analysis performed using liquid medium. A crystal violet binding assay for the assessment of biofilm formation byP. intermediashowed that sub-MICs of polyP3 significantly decreased biofilm formation. Under the scanning electron microscope, decreased numbers ofP. intermediacells forming the biofilms were observed when the bacterial cells were incubated with 0.025% or higher concentrations of polyP3. Assessment of biofilm viability with LIVE/DEAD staining and viable cell count methods showed that 0.05% or higher concentrations of polyP3 significantly decreased the viability of the preformed biofilms in a concentration-dependent manner. The zone sizes of alpha-hemolysis formed on horse blood agar produced byP. intermediawere decreased in the presence of polyP3. The expression of the genes encoding hemolysins and the genes of the hemin uptake (hmu) locus was downregulated by polyP3. Collectively, our results show that polyP is an effective antimicrobial agent againstP. intermediain biofilms as well as planktonic phase, interfering with the process of hemin acquisition by the bacterium.

scholarly journals Exposure of Bacillus subtilis to Low Pressure (5 Kilopascals) Induces Several Global Regulons, Including Those Involved in the SigB-Mediated General Stress Response

2014 ◽  
Vol 80 (16) ◽  
pp. 4788-4794 ◽  
Author(s):  
Samantha M. Waters ◽  
José A. Robles-Martínez ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Subtilis ◽  
Stress Response ◽  
High Pressures ◽  
Low Pressure ◽  
Bacterial Cells ◽  
Content Type ◽  
General Stress Response ◽  
Cellular Processes ◽  
General Stress ◽  
Microbial Responses

ABSTRACTStudies of how microorganisms respond to pressure have been limited mostly to the extreme high pressures of the deep sea (i.e., the piezosphere). In contrast, despite the fact that the growth of most bacteria is inhibited at pressures below ∼2.5 kPa, little is known of microbial responses to low pressure (LP). To study the global LP response, we performed transcription microarrays onBacillus subtiliscells grown under normal atmospheric pressure (∼101 kPa) and a nearly inhibitory LP (5 kPa), equivalent to the pressure found at an altitude of ∼20 km. Microarray analysis revealed altered levels of 363 transcripts belonging to several global regulons (AbrB, CcpA, CodY, Fur, IolR, ResD, Rok, SigH, Spo0A). Notably, the highest number of upregulated genes, 86, belonged to the SigB-mediated general stress response (GSR) regulon. Upregulation of the GSR by LP was confirmed by monitoring the expression of the SigB-dependentctc-lacZreporter fusion. Measuring transcriptome changes resulting from exposure of bacterial cells to LP reveals insights into cellular processes that may respond to LP exposure.

Combined Effect of High Hydrostatic Pressure and Nisin on Loss of Viability, Membrane Damage and Release of Intracellular Contents of Bacillus subtilis and Escherichia coli

2010 ◽  
Vol 6 (5) ◽  
Author(s):  
Wei-Min Qi ◽  
Ping Qian ◽  
Jian-Yong Yu ◽  
Chi-Yu Zhang ◽  
Xiao Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Hydrostatic Pressure ◽  
Synergistic Effect ◽  
High Hydrostatic Pressure ◽  
Cell Envelope ◽  
Membrane Damage ◽  
Combined Effect ◽  
Gram Negative Bacteria ◽  
E Coli

Bacillus subtilis and Escherichia coli were chosen to investigate the combined effect of high hydrostatic pressure (HHP) and Nisin on loss of viability, membrane damage and release of intracellular contents of microorganisms. The results showed that the combination of 200 IU/mL Nisin and HHP exhibited a synergistic effect over 2 log on the inactivation of B. subtilis at pressure 300 MPa. The similar synergistic effect was observed on the membrane damage and release of intracellular contents of B. subtilis. The Nisin alone had no effect against E. coli, which belongs to gram negative bacteria. However, at pressure 300 MPa, Nisin caused the membrane damage from 55% to 80%. The synergistic effect of Nisin and HHP on loss of viability, membrane damage and release of intracellular contents of E. coli were also illustrated when the HHP pressure exceeded 300 MPa as the consequence of the serious changes produced by HHP at higher pressure in the cell envelope. It allows the entry of Nisin molecules to cell membrane.

scholarly journals Long-Term Storage of Vegetable Juices Treated by High Hydrostatic Pressure: Assurance of the Microbial Safety

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Justyna Nasiłowska ◽  
Barbara Sokołowska ◽  
Monika Fonberg-Broczek
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Storage Temperature ◽  
Plate Count ◽  
Bacterial Cells ◽  
Carrot Juice ◽  
Beetroot Juice ◽  
C Storage ◽  
Long Term Storage

Food business operators search for new, mild technologies, which extend the shelf life of product without changing the sensory and nutritional properties. High hydrostatic pressure (HHP) meets these requirements; however it also triggers sublethal injury of bacterial cells. Sublethal injuries could spoil the product during storage and potentially pose major public health concerns. This study aims to examine the changes of sublethally injured pathogens cells in two vegetable juices: carrot juice (pH 6.0-6.7) and beetroot juice (pH 4.0-4.2) that are induced by HHP (300-500 MPa). The possibilities of recovery of bacterial cells during 28 days of juices storage at two different temperatures (5°C and 25°C) were determined using plate count methods. During the entire period of storage of carrot juice at refrigerated temperature, the propagation and regeneration ofL. innocuastrains were observed. Storage at 25°C showed that the number of these bacteria drastically decreased between 14 and 21 days. The above phenomenon was not detected inE. colicase. There was no cells recovery during long-term refrigerated storage for all strains in beetroot juice. However, in some cases spoiling of this product intermittently occurred at 25°C storage temperature. This work demonstrates that carrot juice supports growth and regeneration of HHP-sublethally injuredL. innocua, while beetroot juice can be classified as a safe product.

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