scholarly journals HubP, a Polar Landmark Protein, Regulates Flagellar Number by Assisting in the Proper Polar Localization of FlhG in Vibrio alginolyticus

2016 ◽  
Vol 198 (22) ◽  
pp. 3091-3098 ◽  
Author(s):  
Norihiro Takekawa ◽  
Soojin Kwon ◽  
Noriko Nishioka ◽  
Seiji Kojima ◽  
Michio Homma
Keyword(s):  
Marine Bacterium ◽  
Vibrio Alginolyticus ◽  
Absolute Amount ◽  
Negative Regulators ◽  
Content Type ◽  
Polar Localization ◽  
Cell Pole ◽  
The Absolute ◽  
Flagellar Biogenesis

ABSTRACT The marine bacterium Vibrio alginolyticus has a single polar flagellum, the number of which is regulated positively by FlhF and negatively by FlhG. FlhF is intrinsically localized at the cell pole, whereas FlhG is localized there through putative interactions with the polar landmark protein HubP. Here we focused on the role of HubP in the regulation of flagellar number in V. alginolyticus . Deletion of hubP increased the flagellar number and completely disrupted the polar localization of FlhG. It was thought that the flagellar number is determined primarily by the absolute amount of FlhF localized at the cell pole. Here we found that deletion of hubP increased the flagellar number although it did not increase the polar amount of FlhF. We also found that FlhG overproduction did not reduce the polar localization of FlhF. These results show that the absolute amount of FlhF is not always the determinant of flagellar number. We speculate that cytoplasmic FlhG works as a quantitative regulator, controlling the amount of FlhF localized at the pole, and HubP-anchored polar FlhG works as a qualitative regulator, directly inhibiting the activity of polar FlhF. This regulation by FlhF, FlhG, and HubP might contribute to achieving optimal flagellar biogenesis at the cell pole in V. alginolyticus . IMPORTANCE For regulation of the flagellar number in marine Vibrio , two proteins, FlhF and FlhG, work as positive and negative regulators, respectively. In this study, we found that the polar landmark protein HubP is involved in the regulation of flagellar biogenesis. Deletion of hubP increased the number of flagella without increasing the amount of pole-localizing FlhF, indicating that the number of flagella is not determined solely by the absolute amount of pole-localizing FlhF, which is inconsistent with the previous model. We propose that cytoplasmic FlhG and HubP-anchored polar FlhG negatively regulate flagellar formation through two independent schemes.

scholarly journals Pumilacidin-Like Lipopeptides Derived from Marine Bacterium Bacillus sp. Strain 176 Suppress the Motility of Vibrio alginolyticus

2017 ◽  
Vol 83 (12) ◽  
Author(s):  
Pengyuan Xiu ◽  
Rui Liu ◽  
Dechao Zhang ◽  
Chaomin Sun
Keyword(s):  
Cell Death ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Marine Bacterium ◽  
Vibrio Alginolyticus ◽  
Bacterial Motility ◽  
Great Promise ◽  
Content Type ◽  
Cyclic Lipopeptides

ABSTRACT Bacterial motility is a crucial factor during the invasion and colonization processes of pathogens, which makes it an attractive therapeutic drug target. Here, we isolated a marine bacterium (Vibrio alginolyticus strain 178) from a seamount in the tropical West Pacific that exhibits vigorous motility on agar plates and severe pathogenicity to zebrafish. We found that V. alginolyticus 178 motility was significantly suppressed by another marine bacterium, Bacillus sp. strain 176, isolated from the same niche. We isolated, purified, and characterized two different cyclic lipopeptides (CLPs) from Bacillus sp. 176 using high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy. The two related CLPs have a pumilacidin-like structure and were both effective inhibitors of V. alginolyticus 178 motility. The CLPs differ by only one methylene group in their fatty acid chains. In addition to motility suppression, the CLPs also induced cell aggregation in the medium and reduced adherence of V. alginolyticus 178 to glass substrates. Notably, upon CLP treatment, the expression levels of two V. alginolyticus flagellar assembly genes (flgA and flgP) dropped dramatically. Moreover, the CLPs inhibited biofilm formation in several other strains of pathogenic bacteria without inducing cell death. This study indicates that CLPs from Bacillus sp. 176 show promise as antimicrobial lead compounds targeting bacterial motility and biofilm formation with a low potential for eliciting antibiotic resistance. IMPORTANCE Pathogenic bacteria often require motility to establish infections and subsequently spread within host organisms. Thus, motility is an attractive therapeutic target for the development of novel antibiotics. We found that cyclic lipopeptides (CLPs) produced by marine bacterium Bacillus sp. strain 176 dramatically suppress the motility of the pathogenic bacterium Vibrio alginolyticus strain 178, reduce biofilm formation, and promote cellular aggregation without inducing cell death. These findings suggest that CLPs hold great promise as potential drug candidates targeting bacterial motility and biofilm formation with a low overall potential for triggering antibiotic resistance.

scholarly journals Assembly Mechanism of a Supramolecular MS-Ring Complex To Initiate Bacterial Flagellar Biogenesis in Vibrio Species

2020 ◽  
Vol 202 (16) ◽  
Author(s):  
Hiroyuki Terashima ◽  
Keiichi Hirano ◽  
Yuna Inoue ◽  
Takaya Tokano ◽  
Akihiro Kawamoto ◽  
...  
Keyword(s):  
Cytoplasmic Membrane ◽  
Supramolecular Complex ◽  
Ring Formation ◽  
Content Type ◽  
Bacterial Flagellum ◽  
Cell Pole ◽  
Ring Assembly ◽  
Assembly Mechanism ◽  
Ring Complex ◽  
Flagellar Biogenesis

ABSTRACT The bacterial flagellum is an organelle responsible for motility and has a rotary motor comprising the rotor and the stator. Flagellar biogenesis is initiated by the assembly of the MS-ring, a supramolecular complex embedded in the cytoplasmic membrane. The MS-ring consists of a few dozen copies of the transmembrane FliF protein and is an essential core structure that is a part of the rotor. The number and locations of the flagella are controlled by the FlhF and FlhG proteins in some species. However, there is no clarity on the factors initiating MS-ring assembly or on the contributions of FlhF/FlhG to this process. Here, we show that FlhF and a C-ring component, FliG, facilitate Vibrio MS-ring formation. When Vibrio FliF alone was expressed in Escherichia coli cells, MS-ring formation rarely occurred, indicating a requirement of other factors for MS-ring assembly. Consequently, we investigated if FlhF aided FliF in MS-ring assembly. We found that FlhF allowed green fluorescent protein (GFP)-fused FliF to localize at the cell pole in a Vibrio cell, suggesting that it increases local concentration of FliF at the pole. When FliF was coexpressed with FlhF in E. coli cells, the MS-ring was effectively formed, indicating that FlhF somehow contributes to MS-ring formation. The isolated MS-ring structure was similar to that of the MS-ring formed by Salmonella FliF. Interestingly, FliG facilitates MS-ring formation, suggesting that FliF and FliG assist in each other’s assembly into the MS-ring and C-ring. This study aids in understanding the mechanism behind MS-ring assembly using appropriate spatial/temporal regulations. IMPORTANCE Flagellar formation is initiated by the assembly of the FliF protein into the MS-ring complex, which is embedded in the cytoplasmic membrane. The appropriate spatial/temporal control of MS-ring formation is important for the morphogenesis of the bacterial flagellum. Here, we focus on the assembly mechanism of Vibrio FliF into the MS-ring. FlhF, a positive regulator of the number and location of flagella, recruits the FliF molecules at the cell pole and facilitates MS-ring formation. FliG also facilitates MS-ring formation. Our study showed that these factors control flagellar biogenesis in Vibrio by initiating the MS-ring assembly. Furthermore, it also implies that flagellar biogenesis is a sophisticated system linked with the expression of certain genes, protein localization, and a supramolecular complex assembly.

Modeling product market competition and reporting quality: the transitional economy of China

2017 ◽  
Vol 43 (2) ◽  
pp. 154-166 ◽  
Author(s):  
Amjad Iqbal ◽  
Zia-ur-Rehman Rao ◽  
Muhammad Zubair Tauni ◽  
Khalil Jebran
Keyword(s):  
Market Competition ◽  
Reporting Quality ◽  
Product Market ◽  
Transitional Economy ◽  
Product Market Competition ◽  
Absolute Level ◽  
Content Type ◽  
The Absolute

Purpose The purpose of this paper is to examine the role of product market competition in shaping a firm’s reporting quality (RQ). Design/methodology/approach This research uses an aggregate measure of a firm’s RQ, considering both the absolute level of discretionary accruals (DA) and the quality of accruals, using modified Jones model and Francis et al. (2005) accruals quality model, respectively. Whereas, the Herfindahl-Hirschman index and the Lerner index are used to measure product market competition. Further, this study considers the transitional economy of China and employs panel data estimation techniques for testing the hypothesized relationships. Findings This study finds that firms operating in more competitive industries are associated with higher RQ. This association still prevails when analysis is done using the component measures of RQ (i.e. the absolute level of DA and the quality of accruals). Overall, the empirical results provide evidence on the disciplining role of product market competition among Chinese firms. Practical implications Given the complex governance structures and specific kind of agency problems in Chinese corporations, this study suggests that product market competition may play an external disciplining role to improve the corporate information environment. Originality/value This research explores the role of product market competition for a firm’s RQ in Chinese-listed companies, while the prior studies on the same topic are mostly from the developed countries.

Effect of PlzD, a YcgR homologue of c-di-GMP-binding protein, on polar flagellar motility in Vibrio alginolyticus

2019 ◽  
Vol 166 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Seiji Kojima ◽  
Takuro Yoneda ◽  
Wakako Morimoto ◽  
Michio Homma
Keyword(s):  
Binding Protein ◽  
Subcellular Fractionation ◽  
Inhibitory Effect ◽  
Vibrio Alginolyticus ◽  
Dependent Manner ◽  
Flagellar Motility ◽  
Over Expression ◽  
Polar Localization ◽  
Cell Pole ◽  
Truncated Variants

AbstractYcgR, a cyclic diguanylate (c-di-GMP)-binding protein expressed in Escherichia coli, brakes flagellar rotation by binding to the motor in a c-di-GMP dependent manner and has been implicated in triggering biofilm formation. Vibrio alginolyticus has a single polar flagellum and encodes YcgR homologue, PlzD. When PlzD or PlzD-GFP was highly over-produced in nutrient-poor condition, the polar flagellar motility of V. alginolyticus was reduced. This inhibitory effect is c-di-GMP independent as mutants substituting putative c-di-GMP-binding residues retain the effect. Moderate over-expression of PlzD-GFP allowed its localization at the flagellated cell pole. Truncation of the N-terminal 12 or 35 residues of PlzD abolished the inhibitory effect and polar localization, and no inhibitory effect was observed by deleting plzD or expressing an endogenous level of PlzD-GFP. Subcellular fractionation showed that PlzD, but not its N-terminally truncated variants, was precipitated when over-produced. Moreover, immunoblotting and N-terminal sequencing revealed that endogenous PlzD is synthesized from Met33. These results suggest that an N-terminal extension allows PlzD to localize at the cell pole but causes aggregation and leads to inhibition of motility. In V. alginolyticus, PlzD has a potential property to associate with the polar flagellar motor but this interaction is too weak to inhibit rotation.

scholarly journals INFLUENCE OF CECECTOMY AND DIETARY ANTIBIOTICS ON THE FATE OF INGESTED INTACT GLUCOSINOLATES IN POULTRY

1987 ◽  
Vol 67 (4) ◽  
pp. 1117-1124 ◽  
Author(s):  
B. A. SLOMINSKI ◽  
L. D. CAMPBELL ◽  
N. E. STANGER
Keyword(s):  
Key Words ◽  
Canola Meal ◽  
Absolute Amount ◽  
Gi Tract ◽  
Balance Study ◽  
Thiocyanate Ion ◽  
Series Of Experiments ◽  
The Absolute

A series of experiments involving the use of cecectomized hens and dietary antibiotics as means of controlling hindgut fermentation was conducted to follow the disappearance of intact glucosinolates (IG) from the GI tract of poultry. In addition, a balance study was conducted with colostomized roosters to determine the role of the kidney in the excretion of IG and thiocyanate ion (SCN). Recovery of IG in cecectomized hens was significantly (P < 0.05) higher than in intact hens (80.5 vs. 33.6 mmol 7 d−1). Similarly, IG recovery was significantly (P < 0.05) higher in antibiotic-fed hens than in hens fed no antibiotics. The effect varied among antibiotics with chlorotetracycline and lincomycin showing the greatest response. Both aliphatic and aromatic (glucosinalbin and indoles) IG disappeared from the GI tract to a significantly (P < 0.01) greater extent in intact hens than in cecectomized hens but the absolute amount of disappearance was greater for aliphatic IG than for aromatic IG. Thiocyanate ion (SCN) excretion was high in the urine of colostomized roosters fed canola meal and exceeded intake in antibiotic-fed, cecectomized hens. The biotransformation of absorbed aliphatic IG was indicated as a possible source of the excess SCN. Key words: Poultry, glucosinolates, absorption, cecectomy, antibiotics, thiocyanate ion

scholarly journals Polar Localization Hub Protein PopZ Restrains Adaptor-Dependent ClpXP Proteolysis in Caulobacter crescentus

2018 ◽  
Vol 200 (20) ◽  
Author(s):  
Kamal Kishore Joshi ◽  
Christine M. Battle ◽  
Peter Chien
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Caulobacter Crescentus ◽  
Cycle Progression ◽  
Content Type ◽  
Polar Localization ◽  
Subsequent Degradation ◽  
Data Point

ABSTRACT In Caulobacter crescentus, timely degradation of several proteins by the ClpXP protease is critical for proper cell cycle progression. During the cell cycle, the ClpXP protease, the substrate CtrA, and many other proteins are localized to the stalked pole dependent on a polar interaction hub composed of PopZ protein oligomers. Prior work suggests that the localization of ClpXP, protease substrates, and cofactors is needed for recognition of substrates, such as CtrA, by ClpXP. Here, we formally test this hypothesis by examining the role of PopZ in ClpXP activity and find, surprisingly, that CtrA degradation is enhanced in cells lacking polar localization due to loss of PopZ. The ClpXP adaptor CpdR is required for this enhanced degradation of CtrA and other adaptor-dependent substrates, but adaptor-independent substrate degradation is not affected upon loss of PopZ. We find that overexpression of PopZ also leads to faster degradation of CtrA but is likely due to nonphysiologically relevant recognition of CtrA by ClpXP alone, as loss of CpdR does not affect this enhancement. Our main conclusion is that loss of PopZ, and therefore loss of polar localization, does not result in the loss of ClpXP-regulated proteolysis, as would be predicted from a model which requires polar localization of ClpXP for its activation. Rather, our data point to a model where PopZ normally restrains ClpXP proteolysis by promoting the inactivation of the CpdR adaptor, perhaps through the activity and localization of the CckA kinase. IMPORTANCE Regulated proteolysis is critical for the cell cycle progression of bacteria, such as Caulobacter crescentus. According to one model, this regulated proteolysis requires localization of the ClpXP protease at the stalked pole for its subsequent degradation of substrates, such as CtrA. This study offers evidence that supports an alternative model to explain how localization might influence protein degradation. Using a delocalized in vivo system created by the deletion of a polar organizing protein, PopZ, we show that activation of the ClpXP protease is independent of its polar localization. The data point to a role for PopZ in restraining ClpXP activity, likely by controlling the activity of upstream regulators of protease activity, such as CckA, though changes in its localization.

scholarly journals The Photobacterium damselae subsp. damselae Hemolysins Damselysin and HlyA Are Encoded within a New Virulence Plasmid

2011 ◽  
Vol 79 (11) ◽  
pp. 4617-4627 ◽  
Author(s):  
Amable J. Rivas ◽  
Miguel Balado ◽  
Manuel L. Lemos ◽  
Carlos R. Osorio
Keyword(s):  
Marine Bacterium ◽  
Conjugative Plasmid ◽  
Virulence Plasmid ◽  
Marine Animals ◽  
Fatal Disease ◽  
Content Type ◽  
Wide Range ◽  
Photobacterium Damselae ◽  
Different Levels

ABSTRACTPhotobacterium damselaesubsp.damselae(formerlyVibrio damsela) is a marine bacterium that causes infections and fatal disease in a wide range of marine animals and in humans. Highly hemolytic strains produce damselysin (Dly), a cytolysin encoded by thedlygene that is lethal for mice and has hemolytic activity. We found that Dly is encoded in the highly hemolytic strain RM-71 within a 153,429-bp conjugative plasmid that we dubbed pPHDD1. In addition to Dly, pPHDD1 also encodes a homologue of the pore-forming toxin HlyA. We found a direct correlation between presence of pPHDD1 and a strong hemolytic phenotype in a collection ofP. damselaesubsp.damselaeisolates. Hemolysis was strongly reduced in a doubledly hlyAmutant, demonstrating the role of the two pPHDD1-encoded genes in hemolysis. Interestingly, although singlehlyAanddlymutants showed different levels of hemolysis reduction depending on the erythrocyte source, hemolysis was not abolished in any of the single mutants, suggesting that the hemolytic phenotype is the result of the additive effect of Dly and HlyA. We found that pPHDD1-encodeddlyandhlyAgenes are necessary for full virulence for mice and fish. Our results suggest that pPHDD1 can be considered as a driving force for the emergence of a highly hemolytic lineage ofP. damselaesubsp.damselae.

Transisi Kepemimpinan Dalam Alkitab

2016 ◽  
Vol 1 (1) ◽  
pp. 16-38
Author(s):  
Jonathan Octavianus
Keyword(s):  
New Testament ◽  
Old Testament ◽  
Jesus Christ ◽  
Transition Time ◽  
People Of God ◽  
The Absolute

As every epoch there are there a transition time, on Old Testament like Moses with Joshua, Joshua selected by God an supported fully by Moses, Conversely Moses have liberally to be changed. Like Elijah to Elisha too.Pattern on New Testament there are an examples of transition time too, like Jesus Christ to His Disciples, an transition from Paul to his successor Timothy. This is a heart and soul a big leader, and shall all leadership owners shepherd in church, Christian institution, etc.Which most be remembered in transition of leadership, that people of God leadership, about who will lead, who continue leadership, like a principle in biblical, hence a role of God, is determinant an anoint man which be selected the absolute God choice and constitute all other, but a succession router leader is which have been selected His own. An can be anointed in front of believers.

Long-term management of patients with multiple brain metastases after shaped beam radiosurgery

2004 ◽  
pp. 406-412
Author(s):  
Paul Okunieff ◽  
Michael C. Schell ◽  
Russell Ruo ◽  
E. Ronald Hale ◽  
Walter G. O'Dell ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Tumor Control ◽  
Content Type ◽  
Negative Results ◽  
Multiple Metastases ◽  
Extracranial Disease ◽  
Successful Control ◽  
The Brain

✓ The role of radiosurgery in the treatment of patients with advanced-stage metastatic disease is currently under debate. Previous randomized studies have not consistently supported the use of radiosurgery to treat patients with numbers of brain metastases. In negative-results studies, however, intracranial tumor control was high but extracranial disease progressed; thus, patient survival was not greatly affected, although neurocognitive function was generally maintained until death. Because the future promises improved systemic (extracranial) therapy, the successful control of brain disease is that much more crucial. Thus, for selected patients with multiple metastases to the brain who remain in good neurological condition, aggressive lesion-targeting radiosurgery should be very useful. Although a major limitation to success of this therapy is the lack of control of extracranial disease in most patients, it is clear that well-designed, aggressive treatment substantially decreases the progression of brain metastases and also improves neurocognitive survival. The authors present the management and a methodology for rational treatment of a patient with breast cancer who has harbored 24 brain metastases during a 3-year period.

scholarly journals Vulnerable adults in police custody

2019 ◽  
Vol 22 (1) ◽  
pp. 5-8
Author(s):  
Ian Cummins
Keyword(s):  
Design Methodology ◽  
Research Literature ◽  
Police Custody ◽  
England And Wales ◽  
Content Type ◽  
Increased Risk ◽  
Vulnerable Adults

Purpose The purpose of this paper is to discuss the recent National Appropriate Adult Network (NAAN) report on the role of the appropriate adult. Design/methodology/approach This paper is based on the NAAN report and a review of relevant policy and research literature. Findings There to Help 2 highlights that there are still significant gaps in the provision of appropriate adult schemes across England and Wales. These gaps potentially place vulnerable adults at increased risk. Originality/value This paper is a review of recent research.

Sign in / Sign up

Export Citation Format

Share Document