scholarly journals Quiescent Body as a Reversible Subcellular Structure Formed in Non-growing Bacterial Cells

2017 ◽  
Author(s):  
Jiayu Yu ◽  
Yang Liu ◽  
Huijia Yin ◽  
Zengyi Chang
Keyword(s):  
Cell Growth ◽  
Bacterial Growth ◽  
Lag Time ◽  
Cellular Respiration ◽  
Antibiotic Tolerance ◽  
Bacterial Cells ◽  
Subcellular Structure ◽  
Time Duration ◽  
Highly Correlated

SummaryBacterial cells take a variable lag time and maintain a multi-drug tolerant non-growing state before resuming growth when encountering growth-supportive conditions. Some of them exhibit an extraordinarily long lag, as pathogenic persisters do. It remains unknown on what determines lag time duration. Here, we unveiled a subcellular structure, termed quiescent body, that is formed in bacterial cells entering non-growing state and sequesters selected proteins essential for cell growth. Their formation occurs progressively in each cell and heterogeneously among individual cells. They only dissolve in re-growing cells to release proteins for immediate re-functioning when conditions become fit. Quiescent body, whose degree of formation is highly correlated with duration of lag time or level of antibiotic tolerance, apparently functions as a biological timer for bacterial growth resumption. Further, suppressing their formation, which directly relies on cellular respiration complexes, or promoting their dissolution might be a viable strategy to eradicate persisters.

scholarly journals Maintenance of translational elongation rate underlies the survival of Escherichia coli during oxidative stress

2019 ◽  
Vol 47 (14) ◽  
pp. 7592-7604 ◽  
Author(s):  
Manlu Zhu ◽  
Xiongfeng Dai
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Cell Growth ◽  
Lag Time ◽  
Elongation Rate ◽  
Bacterial Cells ◽  
Defense Proteins ◽  
Oxidative Defense ◽  
Stress Defense

AbstractTo cope with harsh circumstances, bacterial cells must initiate cellular stress response programs, which demands the de novo synthesis of many stress defense proteins. Reactive oxygen species (ROS) is a universal environmental stressor for both prokaryotic cells and eukaryotic cells. However, the physiological burden that limits the survival of bacterial cells during oxidative stress remains elusive. Here we quantitatively characterize the cell growth and translational elongation rate of Escherichia coli cells treated with different doses of hydrogen peroxide. Cell growth is immediately arrested by low to moderate levels of hydrogen peroxide, but completely recovers after a certain lag time. The lag time depends positively on the dose of hydrogen peroxide. During the lag time, translational elongation rate drops by as much as ∼90% at initial stage and recovers to its normal state later, a phenomenon resulting from the dramatic alteration in cellular tRNA pools during oxidative stress. However, translational elongation is completely stalled at a certain threshold-level of hydrogen peroxide, at which cells ultimately fail to resume growth. Although the mRNA transcription of oxidative defense genes in oxyR regulon is dramatically induced upon hydrogen peroxide treatment, the extreme slow-down of translational elongation during high levels of hydrogen peroxide has severely compromised the timely synthesis of those oxidative defense proteins. Our study demonstrates that the tRNA-limited translational elongation is a key physiological bottleneck that the bacteria must overcome to counteract ROS, and the maintenance of translational elongation rate for timely synthesis of stress defense proteins is crucial for cells to smoothly get over the oxidative stress.

scholarly journals Reciprocal hemizygosity analysis reveals that the Saccharomyces cerevisiae CGI121 gene affects lag time duration in synthetic grape must

2021 ◽  
Author(s):  
Runze Li ◽  
Rebecca C Deed
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Low Temperatures ◽  
Lag Time ◽  
Lag Phase ◽  
Phenotypic Traits ◽  
Time Duration ◽  
Phase Duration ◽  
Grape Must ◽  
The Impact ◽  
Reciprocal Hemizygosity Analysis

Abstract It is standard practice to ferment white wines at low temperatures (10-18 °C). However, low temperatures increase fermentation duration and risk of problem ferments, leading to significant costs. The lag duration at fermentation initiation is heavily impacted by temperature; therefore, identification of Saccharomyces cerevisiae genes influencing fermentation kinetics is of interest for winemaking. We selected 28 S. cerevisiae BY4743 single deletants, from a prior list of open reading frames (ORFs) mapped to quantitative trait loci (QTLs) on chromosomes VII and XIII, influencing the duration of fermentative lag time. Five BY4743 deletants, Δapt1, Δcgi121, Δclb6, Δrps17a, and Δvma21, differed significantly in their fermentative lag duration compared to BY4743 in synthetic grape must (SGM) at 15 °C, over 72 h. Fermentation at 12.5 °C for 528 h confirmed the longer lag times of BY4743 Δcgi121, Δrps17a, and Δvma21. These three candidate ORFs were deleted in S. cerevisiae RM11-1a and S288C to perform single reciprocal hemizygosity analysis (RHA). RHA hybrids and single deletants of RM11-1a and S288C were fermented at 12.5 °C in SGM and lag time measurements confirmed that the S288C allele of CGI121 on chromosome XIII, encoding a component of the EKC/KEOPS complex, increased fermentative lag phase duration. Nucleotide sequences of RM11-1a and S288C CGI121 alleles differed by only one synonymous nucleotide, suggesting that intron splicing, codon bias, or positional effects might be responsible for the impact on lag phase duration. This research demonstrates a new role of CGI121 and highlights the applicability of QTL analysis for investigating complex phenotypic traits in yeast.

A microscopy-based approach for determining growth probability and lag time of individual bacterial cells

2020 ◽  
pp. 110052
Author(s):  
Lena Fritsch ◽  
Abirami Baleswaran ◽  
Hélène Bergis ◽  
Adrienne Lintz ◽  
Erwann Hamon ◽  
...  
Keyword(s):  
Lag Time ◽  
Bacterial Cells ◽  
Growth Probability

scholarly journals Enhanced Arsenic Accumulation in Engineered Bacterial Cells Expressing ArsR

2004 ◽  
Vol 70 (8) ◽  
pp. 4582-4587 ◽  
Author(s):  
Jan Kostal ◽  
Rosanna Yang ◽  
Cindy H. Wu ◽  
Ashok Mulchandani ◽  
Wilfred Chen
Keyword(s):  
Cell Growth ◽  
Environmental Protection Agency ◽  
Arsenic Removal ◽  
Fusion Partner ◽  
Resting Cells ◽  
Bacterial Cells ◽  
High Affinity ◽  
Affinity Ligand ◽  
Arsenic Accumulation ◽  
Severe Reduction

ABSTRACT The metalloregulatory protein ArsR, which offers high affinity and selectivity toward arsenite, was overexpressed in Escherichia coli in an attempt to increase the bioaccumulation of arsenic. Overproduction of ArsR resulted in elevated levels of arsenite bioaccumulation but also a severe reduction in cell growth. Incorporation of an elastin-like polypeptide as the fusion partner to ArsR (ELP153AR) improved cell growth by twofold without compromising the ability to accumulate arsenite. Resting cells overexpressing ELP153AR accumulated 5- and 60-fold-higher levels of arsenate and arsenite than control cells without ArsR overexpression. Conversely, no significant improvement in Cd2+ or Zn2+ accumulation was observed, validating the specificity of ArsR. The high affinity of ArsR allowed 100% removal of 50 ppb of arsenite from contaminated water with these engineered cells, providing a technology useful to comply with the newly approved U.S. Environmental Protection Agency limit of 10 ppb. These results open up the possibility of using cells overexpressing ArsR as an inexpensive, high-affinity ligand for arsenic removal from contaminated drinking and ground water.

scholarly journals Enhancement of pyocyanin production by subinhibitory concentration of royal jelly in Pseudomonas aeruginosa

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 14
Author(s):  
Dina Auliya Amly ◽  
Puspita Hajardhini ◽  
Alma Linggar Jonarta ◽  
Heribertus Dedy Kusuma Yulianto ◽  
Heni Susilowati
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Royal Jelly ◽  
Microtiter Plate ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Antibiotic Tolerance ◽  
Subinhibitory Concentration ◽  
Pyocyanin Production

Background: Pseudomonas aeruginosa, a multidrug-resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may potentially overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth, pyocyanin production, and biofilm formation of P. aeruginosa. Methods: Pseudomonas aeruginosa ATCC 10145 and clinical isolates were cultured in a royal jelly-containing medium to test the antibacterial activity. Pyocyanin production was observed by measuring the absorbance at 690 nm after 36 h culture and determined using extinction coefficient 4310 M-1 cm-1. Static microtiter plate biofilm assay performed to detect the biofilm formation, followed by scanning electron microscopy. Results: Royal jelly effectively inhibited the viability of both strains from a concentration of 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC 10145, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Concentrations of 12.5% and 6.125% significantly induced biofilm formation of P. aeruginosa ATCC 10145, in line with the results of the SEM analysis. Conclusions: The royal jelly concentration of 25% or higher inhibits bacterial growth; however, the subinhibitory concentration increases pyocyanin production and biofilm formation in P. aeruginosa. It is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.

scholarly journals Effect of Laser Irradiation on Cell Function and Its Implications in Raman Spectroscopy

2018 ◽  
Vol 84 (8) ◽  
pp. e02508-17 ◽  
Author(s):  
Xiaofei Yuan ◽  
Yanqing Song ◽  
Yizhi Song ◽  
Jiabao Xu ◽  
Yinhu Wu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cell Growth ◽  
Single Cell ◽  
Laser Irradiation ◽  
Living Cells ◽  
Growth Characteristics ◽  
Single Cell Level ◽  
Bacterial Cells ◽  
Cell Level ◽  
Gram Negative

ABSTRACTLasers are instrumental in advanced bioimaging and Raman spectroscopy. However, they are also well known for their destructive effects on living organisms, leading to concerns about the adverse effects of laser technologies. To implement Raman spectroscopy for cell analysis and manipulation, such as Raman-activated cell sorting, it is crucial to identify nondestructive conditions for living cells. Here, we evaluated quantitatively the effect of 532-nm laser irradiation on bacterial cell fate and growth at the single-cell level. Using a purpose-built microfluidic platform, we were able to quantify the growth characteristics, i.e., specific growth rates and lag times of individual cells, as well as the survival rate of a population in conjunction with Raman spectroscopy. Representative Gram-negative and Gram-positive species show similar trends in response to a laser irradiation dose. Laser irradiation could compromise the physiological function of cells, and the degree of destruction is both dose and strain dependent, ranging from reduced cell growth to a complete loss of cell metabolic activity and finally to physical disintegration. Gram-positive bacterial cells are more susceptible than Gram-negative bacterial strains to irradiation-induced damage. By directly correlating Raman acquisition with single-cell growth characteristics, we provide evidence of nondestructive characteristics of Raman spectroscopy on individual bacterial cells. However, while strong Raman signals can be obtained without causing cell death, the variety of responses from different strains and from individual cells justifies careful evaluation of Raman acquisition conditions if cell viability is critical.IMPORTANCEIn Raman spectroscopy, the use of powerful monochromatic light in laser-based systems facilitates the detection of inherently weak signals. This allows environmentally and clinically relevant microorganisms to be measured at the single-cell level. The significance of being able to perform Raman measurement is that, unlike label-based fluorescence techniques, it provides a “fingerprint” that is specific to the identity and state of any (unlabeled) sample. Thus, it has emerged as a powerful method for studying living cells under physiological and environmental conditions. However, the laser's high power also has the potential to kill bacteria, which leads to concerns. The research presented here is a quantitative evaluation that provides a generic platform and methodology to evaluate the effects of laser irradiation on individual bacterial cells. Furthermore, it illustrates this by determining the conditions required to nondestructively measure the spectra of representative bacteria from several different groups.

scholarly journals Effect of Humic Substance Photodegradation on Bacterial Growth and Respiration in Lake Water

2005 ◽  
Vol 71 (10) ◽  
pp. 6267-6275 ◽  
Author(s):  
Alexandre M. Anesio ◽  
Wilhelm Granéli ◽  
George R. Aiken ◽  
David J. Kieber ◽  
Kenneth Mopper
Keyword(s):  
Chemical Composition ◽  
Humic Substance ◽  
Bacterial Growth ◽  
Lake Water ◽  
Standard Error ◽  
Growth Efficiency ◽  
Bacterial Respiration ◽  
Growth Respiration ◽  
Biological Substrates ◽  
Highly Correlated

ABSTRACT This study addresses how humic substance (HS) chemical composition and photoreactivity affect bacterial growth, respiration, and growth efficiency (BGE) in lake water. Aqueous solutions of HSs from diverse aquatic environments representing different dissolved organic matter sources (autochthonous and allochthonous) were exposed to artificial solar UV radiation. These solutions were added to lake water passed through a 0.7-μm-pore-size filter (containing grazer-free lake bacteria) followed by dark incubation for 5, 43, and 65 h. For the 5-h incubation, several irradiated HSs inhibited bacterial carbon production (BCP) and this inhibition was highly correlated with H2O2 photoproduction. The H2O2 decayed in the dark, and after 43 h, nearly all irradiated HSs enhanced BCP (average 39% increase relative to nonirradiated controls, standard error = 7.5%, n = 16). UV exposure of HSs also increased bacterial respiration (by ∼18%, standard error = 5%, n = 4), but less than BCP, resulting in an average increase in BGE of 32% (standard error = 10%, n = 4). Photoenhancement of BCP did not correlate to HS bulk properties (i.e., elemental and chemical composition). However, when the photoenhancement of BCP was normalized to absorbance, several trends with HS origin and extraction method emerged. Absorbance-normalized hydrophilic acid and humic acid samples showed greater enhancement of BCP than hydrophobic acid and fulvic acid samples. Furthermore, absorbance-normalized autochthonous samples showed ∼10-fold greater enhancement of BCP than allochthonous-dominated samples, indicating that the former are more efficient photoproducers of biological substrates.

Micrograzer Impact and Substrate Limitation of Bacterioplankton in Lake Michigan

1990 ◽  
Vol 47 (9) ◽  
pp. 1836-1841 ◽  
Author(s):  
Gwenyth Laird Pernie ◽  
Donald Scavia ◽  
Michael L. Pace ◽  
Hunter J. Carrick
Keyword(s):  
Bacterial Growth ◽  
Growth Rates ◽  
Lake Michigan ◽  
Heterotrophic Bacteria ◽  
Organic Substrate ◽  
Trophic Levels ◽  
Heterotrophic Flagellates ◽  
Bacterial Cells ◽  
Substrate Limitation ◽  
Loss Rates

We estimated Lake Michigan epilimnetic heterotrophic bacterial loss rates, predator size, and substrate limitation in 1986 and 1987. The bacterial growth rates were always enhanced by organic substrate additions indicating that bacterial growth is limited, to some degree, by substrate availablility. In this study we obtained loss rates and intrinsic growth rates each between 0.32 and 1.45 d−1. The grazers were predominantly picoplankton-size organisms, presumably heterotrophic flagellates. Using radiolabeled bacteria, only a small percentage (2–3%) of bacterial cells were incorporated into larger size fractions after 24 h. These results indicate that during our experiments heterotrophic bacteria were not a direct, significant, carbon source for the upper trophic levels.

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