scholarly journals A Small Regulatory RNA Generated from the malK 5′ Untranslated Region Targets Gluconeogenesis in Vibrio Species

mSphere ◽  
2021 ◽  
Author(s):  
Xing Luo ◽  
Marick Esberard ◽  
Philippe Bouloc ◽  
Annick Jacq
Keyword(s):  
Untranslated Region ◽  
Vibrio Species ◽  
Economic Consequences ◽  
Regulatory Rna ◽  
Content Type ◽  
Small Regulatory Rna ◽  
Pacific Oysters ◽  
Summer Mortality

Juvenile pacific oysters have been subject in recent years to summer mortality episodes with deep economic consequences. The pathogen Vibrio tasmaniensis has been associated with such mortality events.

scholarly journals The FasX Small Regulatory RNA Negatively Regulates the Expression of Two Fibronectin-Binding Proteins in Group A Streptococcus

2015 ◽  
Vol 197 (23) ◽  
pp. 3720-3730 ◽  
Author(s):  
Jessica L. Danger ◽  
Nishanth Makthal ◽  
Muthiah Kumaraswami ◽  
Paul Sumby
Keyword(s):  
Cell Surface ◽  
Virulence Factors ◽  
Binding Proteins ◽  
Mrna Translation ◽  
Regulatory Rna ◽  
Collagen Binding ◽  
Content Type ◽  
Small Regulatory Rna ◽  
Group A ◽  
Fibronectin Binding

ABSTRACTThe group AStreptococcus(GAS;Streptococcus pyogenes) causes more than 700 million human infections each year. The success of this pathogen can be traced in part to the extensive arsenal of virulence factors that are available for expression in temporally and spatially specific manners. To modify the expression of these virulence factors, GAS use both protein- and RNA-based regulators, with the best-characterized RNA-based regulator being the small regulatory RNA (sRNA) FasX. FasX is a 205-nucleotide sRNA that contributes to GAS virulence by enhancing the expression of the thrombolytic secreted virulence factor streptokinase and by repressing the expression of the collagen-binding cell surface pili. Here, we have expanded the FasX regulon, showing that this sRNA also negatively regulates the expression of the adhesion- and internalization-promoting, fibronectin-binding proteins PrtF1 and PrtF2. FasX posttranscriptionally regulates the expression of PrtF1/2 through a mechanism that involves base pairing to theprtF1andprtF2mRNAs within their 5′ untranslated regions, overlapping the mRNA ribosome-binding sites. Thus, duplex formation between FasX and theprtF1andprtF2mRNAs blocks ribosome access, leading to an inhibition of mRNA translation. Given that FasX positively regulates the expression of the spreading factor streptokinase and negatively regulates the expression of the collagen-binding pili and of the fibronectin-binding PrtF1/2, our data are consistent with FasX functioning as a molecular switch that governs the transition of GAS between the colonization and dissemination stages of infection.IMPORTANCEMore than half a million deaths each year are a consequence of infections caused by GAS. Insights into how this pathogen regulates the production of proteins during infection may facilitate the development of novel therapeutic or preventative regimens aimed at inhibiting this activity. Here, we have expanded insight into the regulatory activity of the GAS small RNA FasX. In addition to identifying that FasX reduces the abundance of the cell surface-located fibronectin-binding proteins PrtF1/2, fibronectin is present in high abundance in human tissues, and we have determined the mechanism behind this regulation. Importantly, as FasX is the only mechanistically characterized regulatory RNA in GAS, it serves as a model RNA in this and related pathogens.

scholarly journals The Endoribonuclease RNase E Coordinates Expression of mRNAs and Small Regulatory RNAs and Is Critical for the Virulence of Brucella abortus

2020 ◽  
Vol 202 (20) ◽  
Author(s):  
Lauren M. Sheehan ◽  
James A. Budnick ◽  
Jaquille Fyffe-Blair ◽  
Kellie A. King ◽  
Robert E. Settlage ◽  
...  
Keyword(s):  
Brucella Abortus ◽  
Human Infection ◽  
Regulatory Rna ◽  
Sequencing Analysis ◽  
Mrna Levels ◽  
Rnase E ◽  
Content Type ◽  
Regulatory Pathways ◽  
Small Regulatory Rna ◽  
The Impact

ABSTRACT RNases are key regulatory components in prokaryotes, responsible for the degradation and maturation of specific RNA molecules at precise times. Specifically, RNases allow cells to cope with changes in their environment through rapid alteration of gene expression. To date, few RNases have been characterized in the mammalian pathogen Brucella abortus. In the present work, we sought to investigate several RNases in B. abortus and determine what role, if any, they have in pathogenesis. Of the 4 RNases reported in this study, the highly conserved endoribonuclease, RNase E, was found to play an integral role in the virulence of B. abortus. Although rne, which encodes RNase E, is essential in B. abortus, we were able to generate a strain encoding a defective version of RNase E lacking the C-terminal portion of the protein, and this strain (rne-tnc) was attenuated in a mouse model of Brucella infection. RNA-sequencing analysis revealed massive RNA dysregulation in B. abortus rne-tnc, with 122 upregulated and 161 downregulated transcripts compared to the parental strain. Interestingly, several mRNAs related to metal homeostasis were significantly decreased in the rne-tnc strain. We also identified a small regulatory RNA (sRNA), called Bsr4, that exhibited significantly elevated levels in rne-tnc, demonstrating an important role for RNase E in sRNA-mediated regulatory pathways in Brucella. Overall, these data highlight the importance of RNase E in B. abortus, including the role of RNase E in properly controlling mRNA levels and contributing to virulence in an animal model of infection. IMPORTANCE Brucellosis is a debilitating disease of humans and animals globally, and there is currently no vaccine to combat human infection by Brucella spp. Moreover, effective antibiotic treatment in humans is extremely difficult and can lead to disease relapse. Therefore, it is imperative that systems and pathways be identified and characterized in the brucellae so new vaccines and therapies can be generated. In this study, we describe the impact of the endoribonuclease RNase E on the control of mRNA and small regulatory RNA (sRNA) levels in B. abortus, as well as the importance of RNase E for the full virulence of B. abortus. This work greatly enhances our understanding of ribonucleases in the biology and pathogenesis of Brucella spp.

scholarly journals A Small Regulatory RNA Controls Cell Wall Biosynthesis and Antibiotic Resistance

mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Jessica Borgmann ◽  
Sina Schäkermann ◽  
Julia Elisabeth Bandow ◽  
Franz Narberhaus
Keyword(s):  
Antibiotic Resistance ◽  
Agrobacterium Tumefaciens ◽  
Antibiotic Resistance Gene ◽  
Tumor Formation ◽  
Regulatory Rna ◽  
Beta Lactamase ◽  
Microbial Composition ◽  
Ampicillin Resistance ◽  
Content Type ◽  
Small Regulatory Rna

ABSTRACT Small regulatory RNAs play an important role in the adaptation to changing conditions. Here, we describe a differentially expressed small regulatory RNA (sRNA) that affects various cellular processes in the plant pathogen Agrobacterium tumefaciens. Using a combination of bioinformatic predictions and comparative proteomics, we identified nine targets, most of which are positively regulated by the sRNA. According to these targets, we named the sRNA PmaR for peptidoglycan biosynthesis, motility, and ampicillin resistance regulator. Agrobacterium spp. are long known to be naturally resistant to high ampicillin concentrations, and we can now explain this phenotype by the positive PmaR-mediated regulation of the beta-lactamase gene ampC. Structure probing revealed a spoon-like structure of the sRNA, with a single-stranded loop that is engaged in target interaction in vivo and in vitro. Several riboregulators have been implicated in antibiotic resistance mechanisms, such as uptake and efflux transporters, but PmaR represents the first example of an sRNA that directly controls the expression of an antibiotic resistance gene. IMPORTANCE The alphaproteobacterium Agrobacterium tumefaciens is able to infect various eudicots causing crown gall tumor formation. Based on its unique ability of interkingdom gene transfer, Agrobacterium serves as a crucial biotechnological tool for genetic manipulation of plant cells. The presence of hundreds of putative sRNAs in this organism suggests a considerable impact of riboregulation on A. tumefaciens physiology. Here, we characterized the biological function of the sRNA PmaR that controls various processes crucial for growth, motility, and virulence. Among the genes directly targeted by PmaR is ampC coding for a beta-lactamase that confers ampicillin resistance, suggesting that the sRNA is crucial for fitness in the competitive microbial composition of the rhizosphere.

scholarly journals South Africa’s economic response to monetary policy uncertainty

2017 ◽  
Vol 44 (2) ◽  
pp. 282-293 ◽  
Author(s):  
Mehmet Balcilar ◽  
Rangan Gupta ◽  
Charl Jooste
Keyword(s):  
Monetary Policy ◽  
Interest Rates ◽  
Stochastic Volatility ◽  
Stochastic Volatility Model ◽  
Economic Consequences ◽  
Policy Uncertainty ◽  
Dsge Model ◽  
Content Type ◽  
Volatility Model ◽  
Central Bankers

Purpose The purpose of this paper is to study the evolution of monetary policy uncertainty and its impact on the South African economy. Design/methodology/approach The authors use a sign restricted SVAR with an endogenous feedback of stochastic volatility to evaluate the sign and size of uncertainty shocks. The authors use a nonlinear DSGE model to gain deeper insights about the transmission mechanism of monetary policy uncertainty. Findings The authors show that monetary policy volatility is high and constant. Both inflation and interest rates decline in response to uncertainty. Output rebounds quickly after a contemporaneous decrease. The DSGE model shows that the size of the uncertainty shock matters – high uncertainty can lead to a severe contraction in output, inflation and interest rates. Research limitations/implications The authors model only a few variables in the SVAR – thus missing perhaps other possible channels of shock transmission. Practical implications There is a lesson for monetary policy: monetary policy uncertainty, in isolation from general macroeconomic uncertainty, often creates unintended adverse consequences and can perpetuate a weak economic environment. The tasks of central bankers are incredibly difficult. Their models project output and inflation with relatively large uncertainty based on many shocks emanating from various sources. It matters how central bankers react to these expectations and how they communicate the underlying risks associated with setting interest rates. Originality/value This is the first study that looks into monetary policy uncertainty into South Africa using a stochastic volatility model and a nonlinear DSGE model. The results should be very useful for the Central Bank as it highlights how uncertainty, that they create, can have adverse economic consequences.

scholarly journals Natural Disruption of Two Regulatory Networks in Serotype M3 Group A Streptococcus Isolates Contributes to the Virulence Factor Profile of This Hypervirulent Serotype

2014 ◽  
Vol 82 (5) ◽  
pp. 1744-1754 ◽  
Author(s):  
Tram N. Cao ◽  
Zhuyun Liu ◽  
Tran H. Cao ◽  
Kathryn J. Pflughoeft ◽  
Jeanette Treviño ◽  
...  
Keyword(s):  
Virulence Factor ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Group A Streptococcus ◽  
Regulatory System ◽  
Mrna Levels ◽  
Bacterial Strains ◽  
Content Type ◽  
Small Regulatory Rna ◽  
Group A

ABSTRACTDespite the public health challenges associated with the emergence of new pathogenic bacterial strains and/or serotypes, there is a dearth of information regarding the molecular mechanisms that drive this variation. Here, we began to address the mechanisms behind serotype-specific variation between serotype M1 and M3 strains of the human pathogenStreptococcus pyogenes(the group AStreptococcus[GAS]). Spatially diverse contemporary clinical serotype M3 isolates were discovered to contain identical inactivating mutations within genes encoding two regulatory systems that control the expression of important virulence factors, including the thrombolytic agent streptokinase, the protease inhibitor-binding protein-G-related α2-macroglobulin-binding (GRAB) protein, and the antiphagocytic hyaluronic acid capsule. Subsequent analysis of a larger collection of isolates determined that M3 GAS, since at least the 1920s, has harbored a 4-bp deletion in thefasCgene of thefasBCAXregulatory system and an inactivating polymorphism in therivRregulator-encoding gene. ThefasCandrivRmutations in M3 isolates directly affect the virulence factor profile of M3 GAS, as evident by a reduction in streptokinase expression and an enhancement of GRAB expression. Complementation of thefasCmutation in M3 GAS significantly enhanced levels of the small regulatory RNA FasX, which in turn enhanced streptokinase expression. Complementation of therivRmutation in M3 GAS restored the regulation ofgrabmRNA abundance but did not alter capsule mRNA levels. While important, thefasCandrivRmutations do not provide a full explanation for why serotype M3 strains are associated with unusually severe invasive infections; thus, further investigation is warranted.

Do participants in the bond market care about corporate social responsibility? Evidence from China

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jun Hu ◽  
Wenbin Long ◽  
Yu Wang ◽  
Linzi Zhou
Keyword(s):  
Corporate Social Responsibility ◽  
Social Responsibility ◽  
Bond Market ◽  
Economic Consequences ◽  
Corporate Bond ◽  
Bond Pricing ◽  
Content Type ◽  
Market Participants ◽  
Risk Environments ◽  
Corporate Social

PurposeUsing a sample of listed Chinese companies that issued bonds from 2010 to 2019, the authors empirically test the link between CSR and corporate bond pricing, and the mechanism and channels behind this link.Design/methodology/approachThis study systematically examines whether and how corporate social responsibility (CSR) affects the corporate bond market in China.FindingsFirms with better CSR have higher corporate bond credit ratings and lower corporate bond yield spreads. These associations remain stable in robustness checks, including checks that use regional typhoon disaster as an instrumental variable. The effects of CSR are more significant for firms with a worse information environment and for those operating in high-risk environments. Better CSR is associated with less earnings management, fewer financial restatements and less analyst forecast divergence. In addition, the effects of CSR are more pronounced after the 2013 market-oriented reform and when issuers are non-state-owned enterprises.Practical implicationsBecause market participants can incorporate firms' CSR into their decision-making, establishing an effective channel for communicating CSR between issuers and market participants will enhance the effects of CSR.Social implicationsResearchers need to attend to the mechanisms behind the link between CSR and corporate bond pricing, and to the characteristics of strong environmental contingency in emerging markets, specifically the periods and scenarios in which the effects of CSR change.Originality/valueThis study provides systemic evidence that CSR benefits corporate bond pricing through both informational and reputational channels and that the effects of CSR vary by time and firm. These findings enrich the literatures on both the economic consequences of CSR and the determinants of corporate bond pricing, and provide a plausible explanation for mixed findings on the effects of CSR in previous studies.

scholarly journals Role of a Stem-Loop Structure inHelicobacter pylori cagATranscript Stability

2018 ◽  
Vol 87 (2) ◽  
Author(s):  
John T. Loh ◽  
Aung Soe Lin ◽  
Amber C. Beckett ◽  
Mark S. McClain ◽  
Timothy L. Cover
Keyword(s):  
Steady State ◽  
Untranslated Region ◽  
Loop Structure ◽  
Stem Loop ◽  
Content Type ◽  
Transcript Stability ◽  
Protein Levels ◽  
Caga Protein ◽  
Stem Loop Structure ◽  
Steady State Levels

ABSTRACTHelicobacter pyloriCagA is a secreted effector protein that contributes to gastric carcinogenesis. Previous studies showed that there is variation amongH. pyloristrains in the steady-state levels of CagA and that a strain-specific motif downstream of thecagAtranscriptional start site (the +59 motif) is associated with both high levels of CagA and premalignant gastric histology. ThecagA5′ untranslated region contains a predicted stem-loop-forming structure adjacent to the +59 motif. In the current study, we investigated the effect of the +59 motif and the adjacent stem-loop oncagAtranscript levels andcagAmRNA stability. Using site-directed mutagenesis, we found that mutations predicted to disrupt the stem-loop structure resulted in decreased steady-state levels of both thecagAtranscript and the CagA protein. Additionally, these mutations resulted in a decreasedcagAmRNA half-life. Mutagenesis of the +59 motif without altering the stem-loop structure resulted in reduced steady-statecagAtranscript and CagA protein levels but did not affectcagAtranscript stability.cagAtranscript stability was not affected by increased sodium chloride concentrations, an environmental factor known to augmentcagAtranscript levels and CagA protein levels. These results indicate that both a predicted stem-loop structure and a strain-specific +59 motif in thecagA5′ untranslated region influence the levels ofcagAexpression.

scholarly journals The Small Regulatory RNA SyR1/PsrR1 Controls Photosynthetic Functions in Cyanobacteria

2014 ◽  
Vol 26 (9) ◽  
pp. 3661-3679 ◽  
Author(s):  
J. Georg ◽  
D. Dienst ◽  
N. Schurgers ◽  
T. Wallner ◽  
D. Kopp ◽  
...  
Keyword(s):  
Regulatory Rna ◽  
Small Regulatory Rna

scholarly journals LuxS-dependent AI-2 production is not involved in global regulation of natural product biosynthesis inPhotorhabdusandXenorhabdus

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3471 ◽  
Author(s):  
Antje K. Heinrich ◽  
Merle Hirschmann ◽  
Nick Neubacher ◽  
Helge B. Bode
Keyword(s):  
Regulatory System ◽  
Regulatory Rna ◽  
Insect Larvae ◽  
Phenotypic Differences ◽  
Global Regulators ◽  
Autoinducer 2 ◽  
Small Regulatory Rna ◽  
Mutant Strains ◽  
Different Strains

The Gram-negative bacteriaPhotorhabdusandXenorhabdusare known to produce a variety of different natural products (NP). These compounds play different roles since the bacteria live in symbiosis with nematodes and are pathogenic to insect larvae in the soil. Thus, a fine tuned regulatory system controlling NP biosynthesis is indispensable. Global regulators such as Hfq, Lrp, LeuO and HexA have been shown to influence NP production ofPhotorhabdusandXenorhabdus. Additionally, photopyrones as quorum sensing (QS) signals were demonstrated to be involved in the regulation of NP production inPhotorhabdus.In this study, we investigated the role of another possible QS signal, autoinducer-2 (AI-2), in regulation of NP production. The AI-2 synthase (LuxS) is widely distributed within the bacterial kingdom and has a dual role as a part of the activated methyl cycle pathway, as well as being responsible for AI-2 precursor production. We deletedluxSin three different entomopathogenic bacteria and compared NP levels in the mutant strains to the wild type (WT) but observed no difference to the WT strains. Furthermore, the absence of the small regulatory RNAmicA, which is encoded directly upstream ofluxS, did not influence NP levels. Phenotypic differences between theP. luminescens luxSdeletion mutant and an earlier describedluxSdeficient strain ofP. luminescenssuggested that two phenotypically different strains have evolved in different laboratories.

Managing reputation loss in China: in-depth analyses of financial restatements

2016 ◽  
Vol 10 (2) ◽  
pp. 312-345 ◽  
Author(s):  
Peng Wu ◽  
Lei Gao ◽  
Zhibin Chen ◽  
Xiao Li
Keyword(s):  
Crisis Management ◽  
Significant Relationship ◽  
Stock Markets ◽  
Financial Distress ◽  
State Ownership ◽  
Economic Consequences ◽  
Content Type ◽  
Financial Restatement ◽  
Financial Restatements ◽  
Crisis Responses

Purpose This paper aims to investigate, in China stock market, whether the reputation loss of a firm caused by financial restatements will lead to significant economic consequences such as financial distress and how a firm should respond to such a crisis. Design/methodology/approach This paper uses Chinese A-share listed firms from 2004 to 2013 as research samples to test research hypotheses using regression analyses. Findings This paper finds a significant relationship between restatements and financial distress, and such a relationship will be affected by both the type and the magnitude of restatements. More importantly, we find joint effects of restatements and state ownership on financial distress, which provides a unique contribution to the extant literature in restatement, financial distress and crisis management using Chinese stock markets data. It shows that ownership structure, affecting the firm reputation and crisis responses strategies, plays a significant role in consequences of restatements, and it is more important for state-owned enterprises (SOEs) to undertake an appropriate crisis response strategy to reduce the negative impact of restatements. Practical implications The results suggest that the damage to a firm’s reputation caused by restatements is affected by restatement type and state ownership. To reduce the negative consequences and avoid financial distress, firms should consider both the restatement type and their firm characteristics when deciding different actions to respond to restatements. In particular, SOEs should act in a more timely manner and take reputation-rebuilding actions such as taking the responsibility and making apologies and taking prompt remedial actions after restatements to regain the public trust and avoid more serious economic consequences. The Chinese government should strengthen their supervisions of SOEs and put more effort to help SOEs reduce administrative procedures, and to improve the efficiency of the implementation of recovery plans after restatements to reinstate firm credibility. Originality/value First, this paper is among the first to link financial restatement, including the type and magnitude of restatements, with financial distress, and the authors find a significant relationship between restatement type and financial distress in China stock markets. Second, this paper is the first to examine whether there is a joint effect of state ownership and restatements on financial distress. Third, this study examines how the magnitude and pervasiveness of restatements influence financial distress and find that both result in an increase of financial distress. Finally, this paper is among the first to connect crisis management and accounting literature to explain how a reputation loss caused by financial restatement may damage a firm’s value and subsequent performance, and based on which to suggest crisis-responses strategies.

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