scholarly journals Role of Ori in Thermococcus barophilus

2021 ◽  
Author(s):  
Yann Moalic ◽  
Ryan Catchpole ◽  
Elodie Leroy ◽  
Logan Mc Teer ◽  
Valérie Cueff-Gauchard ◽  
...  
Keyword(s):  
Dna Replication ◽  
Genomic Dna ◽  
Replication Origin ◽  
Gene Deletion ◽  
Reference Strain ◽  
Stationary Phases ◽  
Exponential Phase ◽  
Lag Phase ◽  
Origin Of Replication

SummaryThe mechanisms underpinning replication of genomic DNA in Archaea have recently been challenged. Species belonging to two different taxonomic orders grow well in the absence of an origin of replication, challenging the role of the replication origin in these organisms. Here, we pursue the investigation of the particular way some archaea manage their DNA replication with Thermococcus barophilus and the role of Ori in this Archaea. Surprisingly we discovered that T. barophilus uses its Ori all along the growth curve with marked increase at the end of exponential phase. Through gene deletion, we show that Ori utilization requires Cdc6, and that origin deletion results in increased time in lag phase and a moderate decrease of growth rate in mutants. The number of chromosomes are quite similar between both strains during exponential and early stationary phases but differs after 24h of growth where ΔTbOriC has only 6 chromosomes/cell compared to 10 for the reference strain (WT). Following 1hr of growth in fresh media, ΔTbOriC strains contains 3 chromosome copies/cell, whereas the WT contains only 1. We hypothesize that the T. barophilus might degrade DNA to obtain energy to start replication and cell division, whereas the ΔTbOriC must maintain more chromosomal copies in order to initiate DNA replication in the absence of an origin or replication. Finally, we analyzed the role of Ori at temperatures above or below the optimal temperature, revealing that Ori is important to start growth at those temperatures, suggesting that replication origins may be involved in stress response.

Changes of trehalose content and expression of relative genes during the bioethanol fermentation bySaccharomyces cerevisiae

2016 ◽  
Vol 62 (10) ◽  
pp. 827-835 ◽  
Author(s):  
Chenfeng Yi ◽  
Fenglian Wang ◽  
Shijun Dong ◽  
Hao Li
Keyword(s):  
Phase Transition ◽  
Stationary Phase ◽  
Ethanol Tolerance ◽  
Stationary Phases ◽  
Exponential Phase ◽  
Yeast Cells ◽  
Ethanol Stress ◽  
Lag Phase ◽  
Significant Difference ◽  
Trehalose Content

Traditionally, trehalose is considered as a protectant to improve the ethanol tolerance of Saccharomyces cerevisiae. In this study, to clarify the changes and roles of trehalose during the bioethanol fermentation, trehalose content and expression of related genes at lag, exponential, and stationary phases (i.e., 2, 8, and 16 h of batch fermentation process) were determined. Although yeast cells at exponential and stationary phase had higher trehalose content than cells at lag phase (P < 0.01), there was no significant difference in trehalose content between exponential and stationary phases (P > 0.05). Moreover, expression of the trehalose degradation-related genes NTH1 and NTH2 decreased at exponential phase in comparison with that at lag phase; compared with cells at lag phase, cells at stationary phase had higher expression of TPS1, ATH1, NTH1, and NTH2 but lower expression of TPS2. During the lag–exponential phase transition, downregulation of NTH1 and NTH2 promoted accumulation of trehalose, and to some extent, trehalose might confer ethanol tolerance to S. cerevisiae before stationary phase. During the exponential–stationary phase transition, upregulation of TPS1 contributed to accumulation of trehalose, and Tps1 protein might be indispensable in yeast cells to withstand ethanol stress at the stationary phase. Moreover, trehalose would be degraded to supply carbon source at stationary phase.

The Role of the Carboxyterminal Domain of RNA Polymerase II in Regulating Origins of DNA Replication in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 162 (3) ◽  
pp. 1117-1129 ◽  
Author(s):  
Laura Gauthier ◽  
Renata Dziak ◽  
David J H Kramer ◽  
David Leishman ◽  
Xiaomin Song ◽  
...  
Keyword(s):  
Dna Replication ◽  
Rna Polymerase Ii ◽  
Specific Gene ◽  
Origin Of Replication ◽  
Minichromosome Maintenance ◽  
Pol Ii ◽  
Initiation Of Dna Replication ◽  
Stimulation Of ◽  
Significant Stimulatory Effect

Abstract MCM (minichromosome maintenance) proteins function as a replication licensing factor (RLF-M), which contributes to limiting initiation of DNA replication to once per cell cycle. In the present study we show that a truncation of the pol II CTD in a S. cerevisiae strain harboring a mutation in mcm5 partially reverses its ts phenotype and improves maintenance of CEN/ARS minichromosomes. We correlate this phenotype to effects on DNA replication rather than to effects on transcription or specific gene expression. We also demonstrate that a similar truncation of the CTD reduces minichromosome stability and impairs stimulation of DNA replication by trans-activators and that tethering of recombinant pol II CTD to an origin of replication has a significant stimulatory effect on minichromosome stability. Furthermore, we show that pol II is recruited to ARS1. We propose that in S. cerevisiae a mechanism of coordinating pol II transcription and DNA replication is mediated by the CTD of pol II.

scholarly journals Post-translational regulation of the RpoS and PsrA genes in pseudomonas putida WCS358: The role of ClpXP protease

2008 ◽  
Vol 60 (1) ◽  
pp. 1-4
Author(s):  
B. Jovcic ◽  
Jelena Begovic ◽  
Jelena Lozo ◽  
Lj. Topisirovic ◽  
M. Kojic
Keyword(s):  
Western Blot ◽  
Pseudomonas Putida ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Translational Regulation ◽  
Stationary Phases ◽  
Transcriptional Regulators ◽  
Exponential Phase ◽  
Early Exponential Phase

The RpoS and PsrA proteins are key transcriptional regulators that are activated in response to the stationary phase of growth in pseudomonads. This study was designed to establish whether ClpXP (ATP-dependent serine protease) regulates levels of RpoS and PsrA in Pseudomonas putida WCS358. Western blot analysis of P. putida WCS358 protein extracts from the early exponentianl, late exponential, and stationary phases of growth with antibodies against RpoS and PsrA revealed that these proteins are degraded by ClpXP in the early exponential phase of growth. The obtained results demonstrate a role for ClpXP protease in post-translational regulation of proteins encoded by the rpoS and psrA genes in Pseudomonas spp.

scholarly journals Role of p38 in Replication of Trypanosoma brucei Kinetoplast DNA

2006 ◽  
Vol 26 (14) ◽  
pp. 5382-5393 ◽  
Author(s):  
Beiyu Liu ◽  
Henrik Molina ◽  
Dario Kalume ◽  
Akhilesh Pandey ◽  
Jack D. Griffith ◽  
...  
Keyword(s):  
Rna Interference ◽  
Dna Replication ◽  
Mitochondrial Genome ◽  
Dna Synthesis ◽  
Trypanosoma Brucei ◽  
Replication Origin ◽  
Mitochondrial Protein ◽  
Kinetoplast Dna ◽  
Z Dna

ABSTRACT Trypanosomes have an unusual mitochondrial genome, called kinetoplast DNA, that is a giant network containing thousands of interlocked minicircles. During kinetoplast DNA synthesis, minicircles are released from the network for replication as θ-structures, and then the free minicircle progeny reattach to the network. We report that a mitochondrial protein, which we term p38, functions in kinetoplast DNA replication. RNA interference (RNAi) of p38 resulted in loss of kinetoplast DNA and accumulation of a novel free minicircle species named fraction S. Fraction S minicircles are so underwound that on isolation they become highly negatively supertwisted and develop a region of Z-DNA. p38 binds to minicircle sequences within the replication origin. We conclude that cells with RNAi-induced loss of p38 cannot initiate minicircle replication, although they can extensively unwind free minicircles.

scholarly journals Isolation and Characterization of rpoS from a Pathogenic Bacterium, Vibrio vulnificus: Role of σS in Survival of Exponential-Phase Cells under Oxidative Stress

2004 ◽  
Vol 186 (11) ◽  
pp. 3304-3312 ◽  
Author(s):  
Kyung-Je Park ◽  
Min-Jin Kang ◽  
Songhee H. Kim ◽  
Hyun-Jung Lee ◽  
Jae-Kyu Lim ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stationary Phase ◽  
Vibrio Vulnificus ◽  
Stationary Phases ◽  
Exponential Phase ◽  
Knockout Mutant ◽  
Gene Encoding ◽  
Isolation And Characterization ◽  
Multiple Copies

ABSTRACT A gene homologous to rpoS was cloned from a fatal human pathogen, Vibrio vulnificus. The functional role of rpoS in V. vulnificus was accessed by using an rpoS knockout mutant strain. This mutant was impaired in terms of the ability to survive under oxidative stress, nutrient starvation, UV irradiation, or acidic conditions. The increased susceptibility of the V. vulnificus mutant in the exponential phase to H2O2 was attributed to the reduced activity of hydroperoxidase I (HPI). Although σS synthesis was induced and HPI activity reached the maximal level in the stationary phase, the mutant in the stationary phase showed the same susceptibility to H2O2 as the wild-type strain in the stationary phase. In addition, HPII activity, which is known to be controlled by σS in Escherichia coli, was not detectable in V. vulnificus strains under the conditions tested. The mutant in the exponential phase complemented with multiple copies of either the rpoS or katG gene of V. vulnificus recovered both resistance to H2O2 and HPI activity compared with the control strain. Expression of the katG gene encoding HPI in V. vulnificus was monitored by using a katG::luxAB transcriptional fusion. The expression of this gene was significantly reduced by deletion of σS in both the early exponential and late stationary phases. Thus, σS is necessary for increased synthesis and activity of HPI, and σS is required for exponentially growing V. vulnificus to develop the ability to survive in the presence of H2O2.

Peanut rhizobia under salt stress: role of trehalose accumulation in strain ATCC 51466

1995 ◽  
Vol 41 (11) ◽  
pp. 1021-1030 ◽  
Author(s):  
Nora E. Ghittoni ◽  
Miguel A. Bueno
Keyword(s):  
Stationary Phases ◽  
Carbon Sources ◽  
Growth Behavior ◽  
Compatible Solute ◽  
Lag Phase ◽  
Strain Atcc ◽  
Bacterial Cultures ◽  
Patterns Of Utilization ◽  
Rhizobium Sp

Strain ATCC 51466, a motile peanut Rhizobium sp., showed patterns of utilization of diverse carbon sources characteristic of fast growers. Bacteria had periplasmic neutral glucans with molecular weight close to 3000. When the extracellular concentration of NaCl was raised to 400 mM, the lag phase of the culture was prolonged about threefold and the generation time was increased almost twice. The changes in growth behavior of salt-stressed bacteria were accompanied by the full suppression of periplasmic oligoglucans and the accumulation of cellular trehalose. Almost identical changes in cell-associated oligoglucans were observed after exposing peanut Rhizobium sp. strain ATCC 10317 to hypersalinity. When the osmotic pressure of the medium was augmented by the addition of either 200 mM mannitol or 16% (w/v) polyethylene glycol, cells of strain ATCC 51466 contained decreased levels of oligoglucans and accumulated trehalose. On the other hand, the content of cellular trehalose increased throughout logarithmic and stationary phases of growth of strain ATCC 51466 in a medium supplemented with 400 mM NaCl. When bacterial cultures were shifted from hypersaline to basal media, oligoglucans were the only oligosaccharides detected. The addition of 10 mM proline to bacteria grown under hypersalinity led to a 50% decrease in the level of trehalose and to the accumulation of oligoglucans. The addition of 10 mM glycine betaine to bacteria grown under hypersalinity also produced accumulation of oligoglucans, but the level of trehalose did not decrease. The results presented here are consistent with a role for trehalose as a compatible solute in peanut Rhizobium ATCC 51466, and they suggest that exogenously added proline may act as a compatible solute in preference to trehalose.Key words: periplasmic glucans, trehalose, peanut Rhizobium, osmotic stress.

The Formation of Intermediate Product I in a Purified System The Role of Factor IX or of its Precursor and of a Hageman Factor-PTA Fraction

1961 ◽  
Vol 6 (02) ◽  
pp. 224-234 ◽  
Author(s):  
E. T Yin ◽  
F Duckert
Keyword(s):  
Intermediate Product ◽  
Factor Ix ◽  
Assay Method ◽  
Lag Phase ◽  
Factor X ◽  
Haemophilia B ◽  
Hageman Factor ◽  
One Stage ◽  
The One

Summary1. The role of two clot promoting fractions isolated from either plasma or serum is studied in a purified system for the generation of intermediate product I in which the serum is replaced by factor X and the investigated fractions.2. Optimal generation of intermediate product I is possible in the purified system utilizing fractions devoid of factor IX one-stage activity. Prothrombin and thrombin are not necessary in this system.3. The fraction containing factor IX or its precursor, no measurable activity by the one-stage assay method, controls the yield of intermediate product I. No similar fraction can be isolated from haemophilia B plasma or serum.4. The Hageman factor — PTA fraction shortens the lag phase of intermediate product I formation and has no influence on the yield. This fraction can also be prepared from haemophilia B plasma or serum.

Sign in / Sign up

Export Citation Format

Share Document