Articles de revues : « LptC »

1

Dai, Xiaowei, Min Yuan, Yu Lu, Xiaohong Zhu, Chao Liu, Yifan Zheng, Shuyi Si, Lijie Yuan, Jing Zhang et Yan Li. « Identification of a Small Molecule That Inhibits the Interaction of LPS Transporters LptA and LptC ». Antibiotics 11, n^o 10 (10 octobre 2022) : 1385. http://dx.doi.org/10.3390/antibiotics11101385.

Texte intégral

Résumé :

The need for novel antibiotics has become imperative with the increasing prevalence of antibiotic resistance in Gram-negative bacteria in clinics. Acting as a permeability barrier, lipopolysaccharide (LPS) protects Gram-negative bacteria against drugs. LPS is synthesized in cells and transported to the outer membrane (OM) via seven lipopolysaccharide transport (Lpt) proteins (LptA–LptG). Of these seven Lpt proteins, LptC interacts with LptA to transfer LPS from the inner membrane (IM) to the OM, and assembly is aided by LptD/LptE. This interaction among the Lpt proteins is important for the biosynthesis of LPS; therefore, the Lpt proteins, which are significant in the assembly process of LPS, can be a potential target for new antibiotics. In this study, a yeast two-hybrid (Y2H) system was used to screen compounds that could block LPS transport by inhibiting LptA/LptC interaction, which finally disrupts the biosynthesis of the OM. We selected the compound IMB-0042 for this study. Our results suggest that IMB-0042 disrupts LptA/LptC interaction by binding to both LptA and LptC. Escherichia coli cells, when treated with IMB-0042, showed filament morphology, impaired OM integrity, and an accumulation of LPS in the periplasm. IMB-0042 inhibited the growth of Gram-negative bacteria and showed synergistic sensitization to other antibiotics, with low cytotoxicity. Thus, we successfully identified a potential antibacterial agent by using a Y2H system, which blocks the transport of LPS by targeting LptA/LptC interaction in Escherichia coli.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Sperandeo, Paola, Fion K. Lau, Andrea Carpentieri, Cristina De Castro, Antonio Molinaro, Gianni Dehò, Thomas J. Silhavy et Alessandra Polissi. « Functional Analysis of the Protein Machinery Required for Transport of Lipopolysaccharide to the Outer Membrane of Escherichia coli ». Journal of Bacteriology 190, n^o 13 (18 avril 2008) : 4460–69. http://dx.doi.org/10.1128/jb.00270-08.

Texte intégral

Résumé :

ABSTRACT Lipopolysaccharide (LPS) is an essential component of the outer membrane (OM) in most gram-negative bacteria, and its structure and biosynthetic pathway are well known. Nevertheless, the mechanisms of transport and assembly of this molecule at the cell surface are poorly understood. The inner membrane (IM) transport protein MsbA is responsible for flipping LPS across the IM. Additional components of the LPS transport machinery downstream of MsbA have been identified, including the OM protein complex LptD/LptE (formerly Imp/RlpB), the periplasmic LptA protein, the IM-associated cytoplasmic ATP binding cassette protein LptB, and LptC (formerly YrbK), an essential IM component of the LPS transport machinery characterized in this work. Here we show that depletion of any of the proteins mentioned above leads to common phenotypes, including (i) the presence of abnormal membrane structures in the periplasm, (ii) accumulation of de novo-synthesized LPS in two membrane fractions with lower density than the OM, and (iii) accumulation of a modified LPS, which is ligated to repeating units of colanic acid in the outer leaflet of the IM. Our results suggest that LptA, LptB, LptC, LptD, and LptE operate in the LPS assembly pathway and, together with other as-yet-unidentified components, could be part of a complex devoted to the transport of LPS from the periplasmic surface of the IM to the OM. Moreover, the location of at least one of these five proteins in every cellular compartment suggests a model for how the LPS assembly pathway is organized and ordered in space.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Martorana, Alessandra M., Mattia Benedet, Elisa A. Maccagni, Paola Sperandeo, Riccardo Villa, Gianni Dehò et Alessandra Polissi. « Functional Interaction between the Cytoplasmic ABC Protein LptB and the Inner Membrane LptC Protein, Components of the Lipopolysaccharide Transport Machinery in Escherichia coli ». Journal of Bacteriology 198, n^o 16 (31 mai 2016) : 2192–203. http://dx.doi.org/10.1128/jb.00329-16.

Texte intégral

Résumé :

ABSTRACTThe assembly of lipopolysaccharide (LPS) in the outer leaflet of the outer membrane (OM) requires the transenvelope Lpt (lipopolysaccharide transport) complex, made inEscherichia coliof seven essential proteins located in the inner membrane (IM) (LptBCFG), periplasm (LptA), and OM (LptDE). At the IM, LptBFG constitute an unusual ATP binding cassette (ABC) transporter, composed by the transmembrane LptFG proteins and the cytoplasmic LptB ATPase, which is thought to extract LPS from the IM and to provide the energy for its export across the periplasm to the cell surface. LptC is a small IM bitopic protein that binds to LptBFG and recruits LptA via its N- and C-terminal regions, and its role in LPS export is not completely understood. Here, we show that the expression level oflptBis a critical factor for suppressing lethality of deletions in the C-terminal region of LptC and the functioning of a hybrid Lpt machinery that carriesPa-LptC, the highly divergent LptC orthologue fromPseudomonas aeruginosa. We found that LptB overexpression stabilizes C-terminally truncated LptC mutant proteins, thereby allowing the formation of a sufficient amount of stable IM complexes to support growth. Moreover, the LptB level seems also critical for the assembly of IM complexes carryingPa-LptC which is otherwise defective in interactions with theE. coliLptFG components. Overall, our data suggest that LptB and LptC functionally interact and support a model whereby LptB plays a key role in the assembly of the Lpt machinery.IMPORTANCEThe asymmetric outer membrane (OM) of Gram-negative bacteria contains in its outer leaflet an unusual glycolipid, the lipopolysaccharide (LPS). LPS largely contributes to the peculiar permeability barrier properties of the OM that prevent the entry of many antibiotics, thus making Gram-negative pathogens difficult to treat. InEscherichia colithe LPS transporter (the Lpt machine) is made of seven essential proteins (LptABCDEFG) that form a transenvelope complex. Here, we show that increased expression of the membrane-associated ABC protein LptB can suppress defects of LptC, which participates in the formation of the periplasmic bridge. This reveals functional interactions between these two components and supports a role of LptB in the assembly of the Lpt machine.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Lin, Yu-Ling, Li-Yi Chen, Chia-Hung Chen, Yen-Ku Liu, Wei-Tung Hsu, Li-Ping Ho et Kuang-Wen Liao. « A Soybean Oil-Based Liposome-Polymer Transfection Complex as a Codelivery System for DNA and Subunit Vaccines ». Journal of Nanomaterials 2012 (2012) : 1–12. http://dx.doi.org/10.1155/2012/427306.

Texte intégral

Résumé :

Inexpensive liposome-polymer transfection complexes (LPTCs) were developed and used as for DNA or protein delivery. The particle sizes of the LPTCs were in the range of 212.2 to 312.1 nm, and the zetapotential was +38.7 mV. LPTCs condensed DNA and protected DNA from DNase I digestion and efficiently delivered LPTC/DNA complexes in Balb/3T3 cells. LPTCs also enhanced the cellular uptake of antigen in mouse macrophage cells and stimulated TNF-αrelease in naïve mice splenocytes, both indicating the potential of LPTCs as adjuvants for vaccines.In vivostudies were performed usingH. pylorirelative heat shock protein 60 as an antigen model. The vaccination of BALB/c mice with LPTC-complexed DNA and protein enhanced the humoral immune response. Therefore, we developed a DNA and protein delivery system using LPTCs that is inexpensive, and we successfully applied it to the development of a DNA and subunit vaccine.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Schultz, Kathryn M., Jimmy B. Feix et Candice S. Klug. « Disruption of LptA oligomerization and affinity of the LptA-LptC interaction ». Protein Science 22, n^o 11 (21 octobre 2013) : 1639–45. http://dx.doi.org/10.1002/pro.2369.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

6

Hicks, Greg, et Zongchao Jia. « Structural Basis for the Lipopolysaccharide Export Activity of the Bacterial Lipopolysaccharide Transport System ». International Journal of Molecular Sciences 19, n^o 9 (10 septembre 2018) : 2680. http://dx.doi.org/10.3390/ijms19092680.

Texte intégral

Résumé :

Gram-negative bacteria have a dense outer membrane (OM) coating of lipopolysaccharides, which is essential to their survival. This coating is assembled by the LPS (lipopolysaccharide) transport (Lpt) system, a coordinated seven-subunit protein complex that spans the cellular envelope. LPS transport is driven by an ATPase-dependent mechanism dubbed the “PEZ” model, whereby a continuous stream of LPS molecules is pushed from subunit to subunit. This review explores recent structural and functional findings that have elucidated the subunit-scale mechanisms of LPS transport, including the novel ABC-like mechanism of the LptB2FG subcomplex and the lateral insertion of LPS into the OM by LptD/E. New questions are also raised about the functional significance of LptA oligomerization and LptC. The tightly regulated interactions between these connected subcomplexes suggest a pathway that can react dynamically to membrane stress and may prove to be a valuable target for new antibiotic therapies for Gram-negative pathogens.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Schultz, Kathryn M., Matthew A. Fischer, Elizabeth L. Noey et Candice S. Klug. « Disruption of the E. coli LptC dimerization interface and characterization of lipopolysaccharide and LptA binding to monomeric LptC ». Protein Science 27, n^o 8 (9 mai 2018) : 1407–17. http://dx.doi.org/10.1002/pro.3429.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

8

Heng, Yu, Zheyu Yang, Pengyu Cao, Xi Cheng et Lei Tao. « Lateral Involvement in Different Sized Papillary Thyroid Carcinomas Patients with Central Lymph Node Metastasis : A Multi-Center Analysis ». Journal of Clinical Medicine 11, n^o 17 (24 août 2022) : 4975. http://dx.doi.org/10.3390/jcm11174975.

Texte intégral

Résumé :

Objective: To quantitatively predict the probability of lateral lymph node metastasis (LLNM) for papillary thyroid carcinomas (PTC) patients with central lymph node metastasis (CLNM) in order to guide postoperative adjuvant treatment. Methods: Five hundred and three PTC patients with CLNM from three medical centers were retrospectively analyzed. Results: The LLNM rate for all patients was 23.9% (120 in 503), with 15.5% (45 in 291) and 35.4% (75 in 212) for patients with papillary thyroid microcarcinoma (PTMC) and large papillary thyroid carcinoma (LPTC), respectively. Patients with no fewer than five positive central lymph nodes (CLN) exhibited a higher risk of LLNM. For patients with fewer than five positive CLN, a maximum diameter of positive CLN > 0.5 cm and the presence of ipsilateral nodular goiter were identified as independent risk factors of LLNM for papillary thyroid microcarcinoma (PTMC) patients. The independent risk factors of LLNM for large papillary thyroid carcinoma (LPTC) patients included a tumor located in the upper portion of thyroid, maximum tumor diameter ≥ 2.0 cm, maximum diameter of positive CLN > 0.5 cm, and the presence of thyroid capsular invasion. Predictive nomograms were established based on these risk factors for PTMC and LPTC patients, respectively. The accuracy and validity of our newly built models were verified by C-index and calibration curves. PTMC and LPTC patients with fewer than five positive CLN were each stratified into three subgroups based on their nomogram risk scores, and a detailed risk stratification flow chart was established for a more accurate evaluation of LLNM risk in PTC patients. Conclusions: A detailed stratification flow chart for PTC patients with CLNM to quantitatively assess LLNM risk was established, which may aid in clinical decision-making for those patients.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Xiang, Quanju, Haiyan Wang, Zhongshan Wang, Yizheng Zhang et Changjiang Dong. « Characterization of lipopolysaccharide transport protein complex ». Open Life Sciences 9, n^o 2 (1 février 2014) : 131–38. http://dx.doi.org/10.2478/s11535-013-0250-5.

Texte intégral

Résumé :

AbstractLipopolysaccharide (LPS) is an essential component of the outer membranes (OM) of most Gram-negative bacteria, which plays a crucial role in protection of the bacteria from toxic compounds and harsh conditions. The LPS is biosynthesized at the cytoplasmic side of inner membrane (IM), and then transported across the aqueous periplasmic compartment and assembled correctly at the outer membrane. This process is accomplished by seven LPS transport proteins (LptA-G), but the transport mechanism remains poorly understood. Here, we present findings by pull down assays in which the periplasmic component LptA interacts with both the IM complex LptBFGC and the OM complex LptDE in vitro, but not with complex LptBFG. Using purified Lpt proteins, we have successfully reconstituted the seven transport proteins as a complex in vitro. In addition, the LptC may play an essential role in regulating the conformation of LptBFG to secure the lipopolysaccharide from the inner membrane. Our results contribute to the understanding of lipopolysaccharide transport mechanism and will provide a platform to study the detailed mechanism of the LPS transport in vitro.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Schultz, Kathryn M., et Candice S. Klug. « High-Pressure EPR Spectroscopy Studies of the E. coli Lipopolysaccharide Transport Proteins LptA and LptC ». Applied Magnetic Resonance 48, n^o 11-12 (21 septembre 2017) : 1341–53. http://dx.doi.org/10.1007/s00723-017-0948-z.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

11

Baranovskii, Denis, Jan Demner, Sylvia Nürnberger, Alexey Lyundup, Heinz Redl, Morgane Hilpert, Sebastien Pigeot et al. « Engineering of Tracheal Grafts Based on Recellularization of Laser-Engraved Human Airway Cartilage Substrates ». CARTILAGE 13, n^o 1 (janvier 2022) : 194760352210759. http://dx.doi.org/10.1177/19476035221075951.

Texte intégral

Résumé :

Objective Implantation of tissue-engineered tracheal grafts represents a visionary strategy for the reconstruction of tracheal wall defects after resections and may develop into a last chance for a number of patients with severe cicatricial stenosis. The use of a decellularized tracheal substrate would offer an ideally stiff graft, but the matrix density would challenge efficient remodeling into a living cartilage. In this study, we hypothesized that the pores of decellularized laser-perforated tracheal cartilage (LPTC) tissues can be colonized by adult nasal chondrocytes (NCs) to produce new cartilage tissue suitable for the repair of tracheal defects. Design Human, native tracheal specimens, isolated from cadaveric donors, were exposed to decellularized and laser engraving–controlled superficial perforation (300 μm depth). Human or rabbit NCs were cultured on the LPTCs for 1 week. The resulting revitalized tissues were implanted ectopically in nude mice or orthotopically in tracheal wall defects in rabbits. Tissues were assayed histologically and by microtomography analyses before and after implantation. Results NCs were able to efficiently colonize the pores of the LPTCs. The extent of colonization (i.e., percentage of viable cells spanning >300 μm of tissue depth), cell morphology, and cartilage matrix deposition improved once the revitalized constructs were implanted ectopically in nude mice. LPTCs could be successfully grafted onto the tracheal wall of rabbits without any evidence of dislocation or tracheal stenosis, 8 weeks after implantation. Rabbit NCs, within the LPTCs, actively produced new cartilage matrix. Conclusion Implantation of NC-revitalized LPTCs represents a feasible strategy for the repair of tracheal wall defects.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Sperandeo, P., R. Villa, A. M. Martorana, M. Samalikova, R. Grandori, G. Deho et A. Polissi. « New Insights into the Lpt Machinery for Lipopolysaccharide Transport to the Cell Surface : LptA-LptC Interaction and LptA Stability as Sensors of a Properly Assembled Transenvelope Complex ». Journal of Bacteriology 193, n^o 5 (17 décembre 2010) : 1042–53. http://dx.doi.org/10.1128/jb.01037-10.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

13

Vetterli, Stefan U., Katja Zerbe, Maik Müller, Matthias Urfer, Milon Mondal, Shuang-Yan Wang, Kerstin Moehle et al. « Thanatin targets the intermembrane protein complex required for lipopolysaccharide transport inEscherichia coli ». Science Advances 4, n^o 11 (novembre 2018) : eaau2634. http://dx.doi.org/10.1126/sciadv.aau2634.

Texte intégral

Résumé :

With the increasing resistance of many Gram-negative bacteria to existing classes of antibiotics, identifying new paradigms in antimicrobial discovery is an important research priority. Of special interest are the proteins required for the biogenesis of the asymmetric Gram-negative bacterial outer membrane (OM). Seven Lpt proteins (LptA to LptG) associate in most Gram-negative bacteria to form a macromolecular complex spanning the entire envelope, which transports lipopolysaccharide (LPS) molecules from their site of assembly at the inner membrane to the cell surface, powered by adenosine 5′-triphosphate hydrolysis in the cytoplasm. The periplasmic protein LptA comprises the protein bridge across the periplasm, which connects LptB2FGC at the inner membrane to LptD/E anchored in the OM. We show here that the naturally occurring, insect-derived antimicrobial peptide thanatin targets LptA and LptD in the network of periplasmic protein-protein interactions required to assemble the Lpt complex, leading to the inhibition of LPS transport and OM biogenesis inEscherichia coli.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Zhang, Xuelian, Yan Li, Weiwei Wang, Jing Zhang, Yuan Lin, Bin Hong, Xuefu You et al. « Identification of an anti-Gram-negative bacteria agent disrupting the interaction between lipopolysaccharide transporters LptA and LptC ». International Journal of Antimicrobial Agents 53, n^o 4 (avril 2019) : 442–48. http://dx.doi.org/10.1016/j.ijantimicag.2018.11.016.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

15

Ngo, Giang, Martin Centola, Ganna Krasnoselska, Denys Pogoryelov, Özkan Yildiz et Enrico Schleiff. « LptC from Anabaena sp. PCC 7120 : Expression, purification and crystallization ». Protein Expression and Purification 175 (novembre 2020) : 105689. http://dx.doi.org/10.1016/j.pep.2020.105689.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

16

Bi, Wei, Yue Bi, Pengfei Li, Shanshan Hou, Xin Yan, Connor Hensley, Yanrong Zhang et al. « Cardioprotection Effects of LPTC-5 Involve Mitochondrial Protection and Dynamics ». ACS Omega 4, n^o 6 (5 juin 2019) : 9868–77. http://dx.doi.org/10.1021/acsomega.8b02441.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

17

Baeta, Tiago, Karine Giandoreggio-Barranco, Isabel Ayala, Elisabete C. C. M. Moura, Paola Sperandeo, Alessandra Polissi, Jean-Pierre Simorre et Cedric Laguri. « The lipopolysaccharide-transporter complex LptB2FG also displays adenylate kinase activity in vitro dependent on the binding partners LptC/LptA ». Journal of Biological Chemistry 297, n^o 6 (décembre 2021) : 101313. http://dx.doi.org/10.1016/j.jbc.2021.101313.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

18

Schultz, Kathryn M., et Candice S. Klug. « Characterization of and lipopolysaccharide binding to the E. coli LptC protein dimer ». Protein Science 27, n^o 2 (28 octobre 2017) : 381–89. http://dx.doi.org/10.1002/pro.3322.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

19

Schouten, A., A. Gauri et M. Bullard. « P120 : Characteristics and outcomes of patients with neurologic complaints who have an unscheduled return visit to the emergency department within 72 hours ». CJEM 21, S1 (mai 2019) : S107. http://dx.doi.org/10.1017/cem.2019.311.

Texte intégral

Résumé :

Introduction: Patients with neurologic presenting complaints comprised 12.5% of total University of Alberta Emergency Department (ED) visits in 2017. This group of patients has high rates of EMS utilization, admission, and ED resources including diagnostic imaging and consult services. We sought to analyze the characteristics and outcomes of the patients with neurologic complaints who have an unscheduled return visit (URV) to the ED within 72 hours to identify opportunities for improvement in quality and safety of patient care. Methods: Data was extracted from the Emergency Department Information System (EDIS) and National Ambulatory Care System databases to select adult patients presenting to the University of Alberta hospital in 2017 with neurologic complaints as defined by the Canadian Triage and Acuity Scale (CTAS). We additionally selected for return visits to Edmonton Zone EDs within 72 hours. Using standard descriptive statistics, we examined demographic and clinical characteristics of patients with 72-hour URV. Results: Of 8,770 total visits, 674 (7.69%) had a 72-hour URV to an Edmonton zone ED. The URV rate was 9.0% in patients seen by a physician and discharged with approval and 23.4-33.3% in patients who left against medical advice (LAMA), prior to completion of treatment (LPCT), or without being seen by a physician (LWBS). The mean age of URV patients was 45.6 years, 56.5% were male, with a mean ED length of stay of 7.37 hours. The top 5 diagnoses for URV patients were headache, migraine, alcohol related disorders, concussion, and transient ischemic attack. 14.7% of URV patients were admitted, 13.5% LWBS, 1.6% LAMA, 1.6% LPCT, and 66.1% were discharged. Conclusion: The majority of neurologic complaint patients with URV within 72 hours are those who LAMA, LPTC, or LWBS at index visit. The admission rate for URV patients (14.7%) is lower than for the index ED visit (55%), however these patients have high LWBS rates. Identifying strategies to limit the LWBS rate for these patients would reduce return visits and improve the quality and safety of patient care.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Naclerio, George A., et Herman O. Sintim. « Multiple ways to kill bacteria via inhibiting novel cell wall or membrane targets ». Future Medicinal Chemistry 12, n^o 13 (juillet 2020) : 1253–79. http://dx.doi.org/10.4155/fmc-2020-0046.

Texte intégral

Résumé :

The rise of antibiotic-resistant infections has been well documented and the need for novel antibiotics cannot be overemphasized. US FDA approved antibiotics target only a small fraction of bacterial cell wall or membrane components, well-validated antimicrobial targets. In this review, we highlight small molecules that inhibit relatively unexplored cell wall and membrane targets. Some of these targets include teichoic acids-related proteins (DltA, LtaS, TarG and TarO), lipid II, Mur family enzymes, components of LPS assembly (MsbA, LptA, LptB and LptD), penicillin-binding protein 2a in methicillin-resistant Staphylococcus aureus, outer membrane protein transport (such as LepB and BamA) and lipoprotein transport components (LspA, LolC, LolD and LolE). Inhibitors of SecA, cell division protein, FtsZ and compounds that kill persister cells via membrane targeting are also covered.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Sperandeo, Paola, Rachele Cescutti, Riccardo Villa, Cristiano Di Benedetto, Daniela Candia, Gianni Dehò et Alessandra Polissi. « Characterization of lptA and lptB, Two Essential Genes Implicated in Lipopolysaccharide Transport to the Outer Membrane of Escherichia coli ». Journal of Bacteriology 189, n^o 1 (20 octobre 2006) : 244–53. http://dx.doi.org/10.1128/jb.01126-06.

Texte intégral

Résumé :

ABSTRACT The outer membrane (OM) of gram-negative bacteria is an asymmetric lipid bilayer that protects the cell from toxic molecules. Lipopolysaccharide (LPS) is an essential component of the OM in most gram-negative bacteria, and its structure and biosynthesis are well known. Nevertheless, the mechanisms of transport and assembly of this molecule in the OM are poorly understood. To date, the only proteins implicated in LPS transport are MsbA, responsible for LPS flipping across the inner membrane, and the Imp/RlpB complex, involved in LPS targeting to the OM. Here, we present evidence that two Escherichia coli essential genes, yhbN and yhbG, now renamed lptA and lptB, respectively, participate in LPS biogenesis. We show that mutants depleted of LptA and/or LptB not only produce an anomalous LPS form, but also are defective in LPS transport to the OM and accumulate de novo-synthesized LPS in a novel membrane fraction of intermediate density between the inner membrane (IM) and the OM. In addition, we show that LptA is located in the periplasm and that expression of the lptA-lptB operon is controlled by the extracytoplasmic σ factor RpoE. Based on these data, we propose that LptA and LptB are implicated in the transport of LPS from the IM to the OM of E. coli.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Cina, Nicholas P., et Candice S. Klug. « Characterizing the interactions between the LPS transport protein LptC and the ABC transporter LptB2FG ». Biophysical Journal 122, n^o 3 (février 2023) : 56a. http://dx.doi.org/10.1016/j.bpj.2022.11.511.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

23

Wenzel, Cory Q., Frank St. Michael, Jacek Stupak, Jianjun Li, Andrew D. Cox et James C. Richards. « Functional Characterization of Lpt3 and Lpt6, the Inner-Core Lipooligosaccharide Phosphoethanolamine Transferases from Neisseria meningitidis ». Journal of Bacteriology 192, n^o 1 (23 octobre 2009) : 208–16. http://dx.doi.org/10.1128/jb.00558-09.

Texte intégral

Résumé :

ABSTRACT The lipooligosaccharide (LOS) of Neisseria meningitidis contains heptose (Hep) residues that are modified with phosphoethanolamine (PEtn) at the 3 (3-PEtn) and/or 6 (6-PEtn) position. The lpt3 (NMB2010) and lpt6 (NMA0408) genes of N. meningitidis, which are proposed to encode the required HepII 3- and 6-PEtn transferases, respectively, were cloned and overexpressed as C-terminally polyhistidine-tagged fusion proteins in Escherichia coli and found to localize to the inner membrane, based on sucrose density gradient centrifugation. Lpt3-His6 and Lpt6-His6 were purified from Triton X-100-solubilized membranes by nickel chelation chromatography, and dot blot analysis of enzymatic reactions with 3-PEtn- and 6-PEtn-specific monoclonal antibodies demonstrated conclusively that Lpt3 and Lpt6 are phosphatidylethanolamine-dependent LOS HepII 3- and 6-PEtn transferases, respectively, and that both enzymes are capable of transferring PEtn to both fully acylated LOS and de-O-acylated (de-O-Ac) LOS. Further enzymatic studies using capillary electrophoresis-mass spectrometry (MS) demonstrated that both Lpt3 and Lpt6 are capable of transferring PEtn to de-O-Ac LOS molecules already containing PEtn at the 6 and 3 positions of HepII, respectively, demonstrating that there is no obligate order of PEtn addition in the generation of 3,6-di-PEtn LOS moieties in vitro.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Wright, J. Claire, Derek W. Hood, Gaynor A. Randle, Katherine Makepeace, Andrew D. Cox, Jianjun Li, Ronald Chalmers, James C. Richards et E. Richard Moxon. « lpt6, a Gene Required for Addition of Phosphoethanolamine to Inner-Core Lipopolysaccharide of Neisseria meningitidis and Haemophilus influenzae ». Journal of Bacteriology 186, n^o 20 (15 octobre 2004) : 6970–82. http://dx.doi.org/10.1128/jb.186.20.6970-6982.2004.

Texte intégral

Résumé :

ABSTRACT We previously described a gene, lpt3, required for the addition of phosphoethanolamine (PEtn) at the 3 position on the β-chain heptose (HepII) of the inner-core Neisseria meningitidis lipopolysaccharide (LPS), but it has long been recognized that the inner-core LPS of some strains possesses PEtn at the 6 position (PEtn-6) on HepII. We have now identified a gene, lpt6 (NMA0408), that is required for the addition of PEtn-6 on HepII. The lpt6 gene is located in a region previously identified as Lgt-3 and is associated with other LPS biosynthetic genes. We screened 113 strains, representing all serogroups and including disease and carriage strains, for the lpt3 and lpt6 genes and showed that 36% contained both genes, while 50% possessed lpt3 only and 12% possessed lpt6 only. The translated amino acid sequence of lpt6 has a homologue (72.5% similarity) in a product of the Haemophilus influenzae Rd genome sequence. Previous structural studies have shown that all H. influenzae strains investigated have PEtn-6 on HepII. Consistent with this, we found that, among 70 strains representing all capsular serotypes and nonencapsulated H. influenzae strains, the lpt6 homologue was invariably present. Structural analysis of LPS from H. influenzae and N. meningitidis strains where lpt6 had been insertionally inactivated revealed that PEtn-6 on HepII could not be detected. The translated amino acid sequences from the N. meningitidis and H. influenzae lpt6 genes have conserved residues across their lengths and are part of a family of proven or putative PEtn transferases present in a wide range of gram-negative bacteria.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Lee, James, Mingyu Xue, Joseph S. Wzorek, Tao Wu, Marcin Grabowicz, Luisa S. Gronenberg, Holly A. Sutterlin et al. « Characterization of a stalled complex on the β-barrel assembly machine ». Proceedings of the National Academy of Sciences 113, n^o 31 (20 juillet 2016) : 8717–22. http://dx.doi.org/10.1073/pnas.1604100113.

Texte intégral

Résumé :

The assembly of β-barrel proteins into membranes is mediated by an evolutionarily conserved machine. This process is poorly understood because no stable partially folded barrel substrates have been characterized. Here, we slowed the folding of the Escherichia coli β-barrel protein, LptD, with its lipoprotein plug, LptE. We identified a late-stage intermediate in which LptD is folded around LptE, and both components interact with the two essential β-barrel assembly machine (Bam) components, BamA and BamD. We propose a model in which BamA and BamD act in concert to catalyze folding, with the final step in the process involving closure of the ends of the barrel with release from the Bam components. Because BamD and LptE are both soluble proteins, the simplest model consistent with these findings is that barrel folding by the Bam complex begins in the periplasm at the membrane interface.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Huddleston, Hailey P., Jorge Chahla, Safa Gursoy, Brady T. Williams, Navya Dandu, Phillip Malloy, Neal B. Naveen, Brian J. Cole et Adam B. Yanke. « A Comprehensive Description of the Lateral Patellofemoral Complex : Anatomy and Anisometry ». American Journal of Sports Medicine 50, n^o 4 (mars 2022) : 984–93. http://dx.doi.org/10.1177/03635465221078033.

Texte intégral

Résumé :

Background: The lateral patellofemoral complex (LPFC) is an important stabilizer of the patella composed of the lateral retinacular structures including the lateral patellofemoral ligament (LPFL), the lateral patellomeniscal ligament (LPML), and the lateral patellotibial ligament (LPTL). While the isolated anatomy of the LPFL has been previously described, no previous study has investigated the entirety of the LPFC structure, length changes, and radiographic landmarks. An understanding of LPFC anatomy is important in the setting of LPFL injury or previous lateral release resulting in iatrogenic medial instability requiring LPFC reconstruction. Purpose: To both qualitatively and quantitatively describe the anatomy and length changes of the LPFC on gross anatomic dissections and standard radiographic views. Study Design: Descriptive laboratory study. Methods: Ten nonpaired cadaveric specimens were utilized in this study. Specimens were dissected to identify distinct attachments of the LPFL, LPML, and LPTL. Ligament lengths, footprints, and centers of each attachment were described with respect to osseous landmarks using a 3-dimensional coordinate measuring device. Ligament length changes were also assessed from 0° to 90° of flexion. Radiopaque markers were subsequently utilized to describe attachments on standard anteroposterior and lateral radiographic views. Results: The individual elements of the LPFC were identified in all specimens. The LPFL patellar attachment had an average total length of 22.5 mm (range, 18.3-27.5 mm), involving a mean of 59% (range, 50%-75%) of the sagittal patella. Based on the average patellar size, a mean of 63% of the LPFL attached to the patella, and the remainder (11.1 ± 1.4 mm) inserted into the patellar tendon. The femoral attachment of the LPFL had a mean maximum length of 24.4 ± 4.3 mm. The center of the LPFL femoral attachment was a mean distance of 13.5 ± 3.2 mm anterior and distal to the lateral epicondyle. The LPFL demonstrated significant shortening, especially in the first 45° of flexion (7.5 ± 5.1 mm). In contrast, the LPTL (5.5 ± 3.0 mm) and LPML (10.0 ± 3.3 mm) demonstrated significant shortening from 45° to 90°. On lateral radiographs, the center of the femoral attachment of the LPFL was a mean total distance of 19.2 ± 7.2 mm from the lateral epicondyle. Conclusion: The most important findings of this study were the correlative anatomy of 3 distinct lateral patellar ligaments (LPFL, LPML, and LPTL) and their anisometry through flexion. All 3 components demonstrated significant shortening during flexion. The quantitative and radiographic measurements detailed the LPFL osseous attachment on the patella; soft tissue attachment on the patellar tendon; and finally, the osseous insertion on the femur distal and anterior to the lateral epicondyle. Similarly, the authors documented the meniscal insertion of the LPML and defined a patellar insertion of the LPTL and LPML as a single attachment. These data allow for reproducible landmarks to aid in the understanding and reconstruction of the lateral patellar restraints. Clinical Relevance: The data produced from this investigation provide a comprehensive description of these 3 lateral patellar stabilizers (LPFL, LPML, LPTL). These data can be used intraoperatively to facilitate anatomic reconstructions of the lateral patellar stabilizers.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Tran, An X., Changjiang Dong et Chris Whitfield. « Structure and Functional Analysis of LptC, a Conserved Membrane Protein Involved in the Lipopolysaccharide Export Pathway inEscherichia coli ». Journal of Biological Chemistry 285, n^o 43 (18 août 2010) : 33529–39. http://dx.doi.org/10.1074/jbc.m110.144709.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

28

Tran, An X., Changjiang Dong et Chris Whitfield. « Structure and functional analysis of LptC, a conserved membrane protein involved in the lipopolysaccharide export pathway inEscherichia coli. » Journal of Biological Chemistry 292, n^o 45 (10 novembre 2017) : 18731. http://dx.doi.org/10.1074/jbc.aac117.000510.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

29

Guyomarc'h, Julien, François-X. Merlin, Hélène Budzinski, Laurent Mazeas, Christian Chaumery, Frank Haeseler et Jean Oudot. « The Erika Oil Spill : Laboratory Studies Conducted To Assist Responders ». International Oil Spill Conference Proceedings 2001, n^o 1 (1 mars 2001) : 637–47. http://dx.doi.org/10.7901/2169-3358-2001-1-637.

Texte intégral

Résumé :

ABSTRACT Immediately following the Erika oil spill, responders raised many questions concerning the identification of the fuel oil, its behavior in the water column, and physical properties, potential toxicity, environmental impacts, and the feasibility of various countermeasures to treat the spill. Several laboratories in France conducted simultaneous complementary investigations. The Laboratoire d'Analyse de Surveillance et d'Expertise de la Marine (LASEM) performed oil analyses of various samples collected at sea and on the shore for identification as well as for confirming the oil drifting predictions. The CEntre de Documentation de Recherche et d'Expérimentations sur les pollutions accidentelles des eaux (CEDRE) studied oil behavior and its physical properties under realistic conditions in its flume test canal to predict the evolution of the product spilled at sea. Simultaneously, the Institut Français du Pétrole (IFP) and the Laboratoire de Physico-Toxico Chimie des systèmes naturels (LPTC) carried out oil chemical analyses of the polyaromatic compounds and the water accommodated fractions for environmental risk assessments. Finally, Muséum National d'Histoire Naturelle (MNHN) investigated the possibility for oil biodegradation through laboratory experiments. This experimental information was of great interest for response operations. Field observations validated laboratory predictions, especially those concerning physical properties.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Benedet, Mattia, Federica A. Falchi, Simone Puccio, Cristiano Di Benedetto, Clelia Peano, Alessandra Polissi et Gianni Dehò. « The Lack of the Essential LptC Protein in the Trans-Envelope Lipopolysaccharide Transport Machine Is Circumvented by Suppressor Mutations in LptF, an Inner Membrane Component of the Escherichia coli Transporter ». PLOS ONE 11, n^o 8 (16 août 2016) : e0161354. http://dx.doi.org/10.1371/journal.pone.0161354.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

31

Myszka, Kamila, Natalia Tomaś, Łukasz Wolko, Artur Szwengiel, Anna Grygier, Katarzyna Nuc et Małgorzata Majcher. « In situ approaches show the limitation of the spoilage potential of Juniperus phoenicea L. essential oil against cold-tolerant Pseudomonas fluorescens KM24 ». Applied Microbiology and Biotechnology 105, n^o 10 (mai 2021) : 4255–68. http://dx.doi.org/10.1007/s00253-021-11338-3.

Texte intégral

Résumé :

Abstract The present study aimed to elucidate the effect of subinhibitory concentrations (sub-MICs) of juniper essential oil (EO), α-pinene, and sabinene on the quorum-sensing (QS)–mediated proteolytic and lipolytic properties of Pseudomonas fluorescens KM24. These activities were verified under in situ conditions, in which sub-MICs of the agents altered the morphology of KM24 cells. RNA-Seq studies revealed key coding sequences (CDSs)/genes related to QS and the proteolytic/lipolytic activities of pseudomonads. In this work, all the examined agents decreased autoinducer synthesis and influenced the mRNA expression of the encoding acyltransferase genes lptA, lptD, and plsB. The highest reduction on the 3rd and 5th days of cultivation was observed for the genes lptD (−5.5 and −5.61, respectively) and lptA (−3.5 and −4.0, respectively) following treatment with EO. Inhibition of the lptA, lptD, and plsB genes by singular constituents of EO was on average, from −0.4 to −0.7. At 5 days of cultivation the profile of AHLs of the reference P. fluorescens KM24 strain consisted of 3-oxo-C14-HSL, 3-oxo-C6-HSL, C4-HSL, and N-[(RS)-3-hydroxybutyryl]-HSL, the concentrations of which were 0.570, 0.018, 3.744, and 0.554 μg ml−1, respectively. Independent of the incubation time, EO, α-pinene, and sabinene also suppressed the protease genes prlC (−1.5, −0.5, and −0.5, respectively) and ctpB (−1.5, −0.7, and −0.4, respectively). Lipolysis and transcription of the lipA/lipB genes were downregulated by the agents on average from −0.3 to −0.6. α-Pinene- and sabinene-rich juniper EO acts as an anti-quorum-sensing agent and can repress the spoilage phenotype of pseudomonads. Key points: Juniper EO, α-pinene, sabinene exhibited anti-QS potential toward KM24. RNA-Seq revealed key CDSs/genes related to QS/proteolytic/lipolytic activities of KM24. Agents at sub-MIC levels influenced the mRNA expression of QS/lipase/protease genes.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Abasi, Mohsen, et Mohammad Bagher Ghaznavi-Ghoushchi. « Low-Power Themes Classifier (LPTC) : A Human-Expert-Based Approach for Classification of Scientific Papers/Theses with Low-Power Theme ». Intelligent Information Management 04, n^o 06 (2012) : 364–82. http://dx.doi.org/10.4236/iim.2012.46041.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

33

Marchesini, María Inés, Ansgar Poetsch, Leticia Soledad Guidolín et Diego J. Comerci. « Brucella abortus Encodes an Active Rhomboid Protease : Proteome Response after Rhomboid Gene Deletion ». Microorganisms 10, n^o 1 (6 janvier 2022) : 114. http://dx.doi.org/10.3390/microorganisms10010114.

Texte intégral

Résumé :

Rhomboids are intramembrane serine proteases highly conserved in the three domains of life. Their key roles in eukaryotes are well understood but their contribution to bacterial physiology is still poorly characterized. Here we demonstrate that Brucella abortus, the etiological agent of the zoonosis called brucellosis, encodes an active rhomboid protease capable of cleaving model heterologous substrates like Drosophila melanogaster Gurken and Providencia stuartii TatA. To address the impact of rhomboid deletion on B. abortus physiology, the proteomes of mutant and parental strains were compared by shotgun proteomics. About 50% of the B. abortus predicted proteome was identified by quantitative proteomics under two experimental conditions and 108 differentially represented proteins were detected. Membrane associated proteins that showed variations in concentration in the mutant were considered as potential rhomboid targets. This class included nitric oxide reductase subunit C NorC (Q2YJT6) and periplasmic protein LptC involved in LPS transport to the outer membrane (Q2YP16). Differences in secretory proteins were also addressed. Differentially represented proteins included a putative lytic murein transglycosylase (Q2YIT4), nitrous-oxide reductase NosZ (Q2YJW2) and high oxygen affinity Cbb3-type cytochrome c oxidase subunit (Q2YM85). Deletion of rhomboid had no obvious effect in B. abortus virulence. However, rhomboid overexpression had a negative impact on growth under static conditions, suggesting an effect on denitrification enzymes and/or high oxygen affinity cytochrome c oxidase required for growth in low oxygen tension conditions.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Yang, Wen-Chieh, Yu-Mei Lin, Yi-Sheng Cheng et Chiu-Ping Cheng. « Ralstonia solanacearum RSc0411 (lptC) is a determinant for full virulence and has a strain-specific novel function in the T3SS activity ». Microbiology 159, Pt_6 (1 juin 2013) : 1136–48. http://dx.doi.org/10.1099/mic.0.064915-0.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

35

Reinacher-Schick, Anke C., Stefanie Noepel-Duennebacke, Jan Hertel, Andrea Tannapfel, Dirk Arnold, Axel Hinke et Susanna Hegewisch-Becker. « Localization of the primary tumor (LPT) and maintenance strategies after first line oxaliplatin (Ox), fluoropyrimidine (FP), and bevacizumab (Bev) in metastatic colorectal cancer (mCRC) : Results from the AIO 0207 trial. » Journal of Clinical Oncology 35, n^o 15_suppl (20 mai 2017) : 3543. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.3543.

Texte intégral

Résumé :

3543 Background: Numerous trials have examined the prognostic and predictive value of the LPT in mCRC, but little is known about the predictive value of LPT on different maintenance strategies. We analyzed progression-free survival (PFS) and overall survival (OS) from start of maintenance according to LPT in patients (pts) from the AIO KRK 0207 trial. Methods: Following a 24-week standard induction 471 pts were randomized to FP/Bev, Bev mono or no treatment with 454 pts being evaluable for PFS. Right sided primary tumors were defined as located in the caecum, ascending colon, transverse colon up to the splenic flexure; left colon was defined as splenic flexure, descending and sigmoid colon and rectum. Results: Data on LPT was available in 414 pts. for PFS (91%). LPT was left sided (LPTl) in 291 (70%) and right-sided (LPTr) in 123 (30%) of pts, respectively (remaining pts: status was either unknown, n = 37 or LPT was located in both regions, n = 3). Median PFS1 was 3.9 months (mos.) for LPTr and 5.3 mos. for LPTl (p = 0.11; HR 1.19, 95%CI 0.96 - 1.48). Analyses on PFS did not demonstrate a major predictive impact of LPT on the efficacy of the three maintenance strategies. The pairwise comparison of treatment arms showed a better PFS for FP/Bev vs no treatment independent from LPT (left: p < 0.0001; HR = 2.39, 95%CI 1.73-3.31; right: p = 0.011; HR 1.78, 95%CI 1.14-2.80). In addition, Bev mono vs no treatment was superior in LPTl (p = 0.0032; HR 1.54, 95%CI 1.15-2.06) with less difference in LPTr (p = 0.17; HR 1.36, 95%CI 0.87-2.14). Analysis for OS (429 evaluable pts) confirmed the strong prognostic impact of LPT (left vs right: 24.0 vs 16.7 months; p < 0.0001; HR = 1.65, 95%CI 1.32 - 2.06), but without major interaction between LPT and maintenance arms. The impact related to RAS mutational status will be reported. Conclusions: The strong prognostic factor of the LPT is confirmed in pts with mCRC undergoing Ox/FP/Bev induction therapy while there seems to be no major predictive impact of LPT on different maintenance strategies. Clinical trial information: EudraCT-Nr: 2008-007974-39.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Fernández, Lucía, Carolina Álvarez-Ortega, Irith Wiegand, Jorge Olivares, Dana Kocíncová, Joseph S. Lam, José Luis Martínez et Robert E. W. Hancock. « Characterization of the Polymyxin B Resistome of Pseudomonas aeruginosa ». Antimicrobial Agents and Chemotherapy 57, n^o 1 (15 octobre 2012) : 110–19. http://dx.doi.org/10.1128/aac.01583-12.

Texte intégral

Résumé :

ABSTRACTMultidrug resistance inPseudomonas aeruginosais increasingly becoming a threat for human health. Indeed, some strains are resistant to almost all currently available antibiotics, leaving very limited choices for antimicrobial therapy. In many such cases, polymyxins are the only available option, although as their utilization increases so does the isolation of resistant strains. In this study, we screened a comprehensive PA14 mutant library to identify genes involved in changes of susceptibility to polymyxin B inP. aeruginosa. Surprisingly, our screening revealed that the polymyxin B resistome of this microorganism is fairly small. Thus, only one resistant mutant and 17 different susceptibility/intrinsic resistance determinants were identified. Among the susceptible mutants, a significant number carried transposon insertions in lipopolysaccharide (LPS)-related genes. LPS analysis revealed that four of these mutants (galU,lptC,wapR, andssg) had an altered banding profile in SDS-polyacrylamide gels and Western blots, with three of them exhibiting LPS core truncation and lack of O-antigen decoration. Further characterization of these four mutants showed that their increased susceptibility to polymyxin B was partly due to increased basal outer membrane permeability. Additionally, these mutants also lacked the aminoarabinose-substituted lipid A species observed in the wild type upon growth in low magnesium. Overall, our results emphasize the importance of LPS integrity and lipid A modification in resistance to polymyxins inP. aeruginosa, highlighting the relevance of characterizing the genes that affect biosynthesis of cell surface structures in this pathogen to follow the evolution of peptide resistance in the clinic.

Styles APA, Harvard, Vancouver, ISO, etc.

37

Botos, Istvan, Nicholas Noinaj et Susan K. Buchanan. « Insertion of proteins and lipopolysaccharide into the bacterial outer membrane ». Philosophical Transactions of the Royal Society B : Biological Sciences 372, n^o 1726 (19 juin 2017) : 20160224. http://dx.doi.org/10.1098/rstb.2016.0224.

Texte intégral

Résumé :

The bacterial outer membrane contains phospholipids in the inner leaflet and lipopolysaccharide (LPS) in the outer leaflet. Both proteins and LPS must be frequently inserted into the outer membrane to preserve its integrity. The protein complex that inserts LPS into the outer membrane is called LptDE, and consists of an integral membrane protein, LptD, with a separate globular lipoprotein, LptE, inserted in the barrel lumen. The protein complex that inserts newly synthesized outer-membrane proteins (OMPs) into the outer membrane is called the BAM complex, and consists of an integral membrane protein, BamA, plus four lipoproteins, BamB, C, D and E. Recent structural and functional analyses illustrate how these two complexes insert their substrates into the outer membrane by distorting the membrane component (BamA or LptD) to directly access the lipid bilayer. This article is part of the themed issue ‘Membrane pores: from structure and assembly, to medicine and technology’.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Xiang, Quanju, Jie Wang, Peng Qin, Bilal Adil, Kaiwei Xu, Yunfu Gu, Xiumei Yu et al. « Effect of common bean seed exudates on growth, lipopolysaccharide production, and lipopolysaccharide transport gene expression of Rhizobium anhuiense ». Canadian Journal of Microbiology 66, n^o 3 (mars 2020) : 186–93. http://dx.doi.org/10.1139/cjm-2019-0413.

Texte intégral

Résumé :

Lipopolysaccharide (LPS) is essential for successful nodulation during the symbiosis of rhizobia and legumes. However, the detailed mechanism of the LPS in this process has not yet been clearly elucidated. In this study, the effects of common bean seed exudates on the growth, lipopolysaccharide production, and lipopolysaccharide transport genes expression (lpt) of Rhizobium anhuiense were investigated. Rhizobium anhuiense exposed to exudates showed changes in LPS electrophoretic profiles and content, whereby the LPS band was wider and the LPS content was higher in R. anhuiense treated with seed exudates. Exudates enhanced cell growth of R. anhuiense in a concentration-dependent manner; R. anhuiense exposed to higher doses of the exudate showed faster growth. Seven lpt genes of R. anhuiense were amplified and sequenced. Sequences of six lpt genes, except for lptE, were the same as those found in previously analyzed R. anhuiense strains, while lptE shared low sequence similarity with other strains. Exposure to the exudates strongly stimulated the expression of all lpt genes. Approximately 6.7- (lptG) to 301-fold (lptE) increases in the transcriptional levels were observed after only 15 min of exposure to exudates. These results indicate that seed exudates affect the LPS by making the cell wall structure more conducive to symbiotic nodulation.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Grabowicz, M., J. Yeh et T. J. Silhavy. « Dominant Negative lptE Mutation That Supports a Role for LptE as a Plug in the LptD Barrel ». Journal of Bacteriology 195, n^o 6 (11 janvier 2013) : 1327–34. http://dx.doi.org/10.1128/jb.02142-12.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

40

Hsueh, Yi-Ching, Eva-M. Brouwer, Julian Marzi, Oliver Mirus et Enrico Schleiff. « Functional properties of LptA and LptD in Anabaena sp. PCC 7120 ». Biological Chemistry 396, n^o 9-10 (1 septembre 2015) : 1151–62. http://dx.doi.org/10.1515/hsz-2014-0322.

Texte intégral

Résumé :

Abstract Lipopolysaccharides (LPS) are central components of the outer membrane and consist of Lipid A, the core polysaccharide, and the O-antigen. The synthesis of LPS is initiated at the cytosolic face of the cytoplasmic membrane. The subsequent transport to and across the outer membrane involves multiple lipopolysaccharide transport (Lpt) proteins. Among those proteins, the periplasmic-localized LptA and the outer membrane-embedded LptD participate in the last steps of transfer and insertion of LPS into the outer membrane. While the process is described for proteobacterial model systems, not much is known about the machinery in cyanobacteria. We demonstrate that anaLptD (alr1278) of Anabaena sp. PCC 7120 is important for cell wall function and its pore domain shows a Lipid A sensitive cation-selective gating behavior. The N-terminal domain of anaLptD recognizes anaLptA (alr4067), but not ecLptA. Furthermore, anaLptA specifically interacts with the Lipid A from Anabaena sp. PCC 7120 only, while anaLptD binds to Lipid A isolated from Escherichia coli as well. Based on the comparative analysis of proteins from E. coli and Anabaena sp. we discuss the properties of the cyanobacterial Lpt system.

Styles APA, Harvard, Vancouver, ISO, etc.

41

Romagnoli, P. « Serum (LPTS) and ascitic leptin (LPTA) levels in decompensated cirrhotic patients ». Journal of Hepatology 34 (avril 2001) : 203. http://dx.doi.org/10.1016/s0168-8278(01)80747-9.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

42

Romagnoli, P., F. Botta, A. Fasoli, G. Tenconi, E. Giannini, T. Barreca et R. Testa. « Serum (LPTS) and ascitic leptin (LPTA) levels in decompensated cirrhotic patients ». Journal of Hepatology 34 (avril 2001) : 202. http://dx.doi.org/10.1016/s0168-8278(01)81622-6.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

43

Svanberg Frisinger, Frida, Bimal Jana, Stefano Donadio et Luca Guardabassi. « In silico Prediction and Prioritization of Novel Selective Antimicrobial Drug Targets in Escherichia coli ». Antibiotics 10, n^o 6 (25 mai 2021) : 632. http://dx.doi.org/10.3390/antibiotics10060632.

Texte intégral

Résumé :

Novel antimicrobials interfering with pathogen-specific targets can minimize the risk of perturbations of the gut microbiota (dysbiosis) during therapy. We employed an in silico approach to identify essential proteins in Escherichia coli that are either absent or have low sequence identity in seven beneficial taxa of the gut microbiota: Faecalibacterium, Prevotella, Ruminococcus, Bacteroides, Lactobacillus, Lachnospiraceae and Bifidobacterium. We identified 36 essential proteins that are present in hyper-virulent E. coli ST131 and have low similarity (bitscore < 50 or identity < 30% and alignment length < 25%) to proteins in mammalian hosts and beneficial taxa. Of these, 35 are also present in Klebsiella pneumoniae. None of the proteins are targets of clinically used antibiotics, and 3D structure is available for 23 of them. Four proteins (LptD, LptE, LolB and BamD) are easily accessible as drug targets due to their location in the outer membrane, especially LptD, which contains extracellular domains. Our results indicate that it may be possible to selectively interfere with essential biological processes in Enterobacteriaceae that are absent or mediated by unrelated proteins in beneficial taxa residing in the gut. The identified targets can be used to discover antimicrobial drugs effective against these opportunistic pathogens with a decreased risk of causing dysbiosis.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Aggarwal, Gaurav, et Latika Singh. « Classification of intellectual disability using LPC, LPCC, and WLPCC parameterization techniques ». International Journal of Computers and Applications 41, n^o 6 (27 mai 2018) : 470–79. http://dx.doi.org/10.1080/1206212x.2018.1475330.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

45

Bos, Martine P., et Jan Tommassen. « The LptD Chaperone LptE Is Not Directly Involved in Lipopolysaccharide Transport inNeisseria meningitidis ». Journal of Biological Chemistry 286, n^o 33 (24 juin 2011) : 28688–96. http://dx.doi.org/10.1074/jbc.m111.239673.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

46

Alexander, Dylan C., Jessica Rock, Jian-Qiao Gu, Carmela Mascio, Min Chu, Paul Brian et Richard H. Baltz. « Production of novel lipopeptide antibiotics related to A54145 by Streptomyces fradiae mutants blocked in biosynthesis of modified amino acids and assignment of lptJ, lptK and lptL gene functions ». Journal of Antibiotics 64, n^o 1 (24 novembre 2010) : 79–87. http://dx.doi.org/10.1038/ja.2010.138.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

47

Lo Sciuto, Alessandra, Alessandra M. Martorana, Regina Fernández-Piñar, Carmine Mancone, Alessandra Polissi et Francesco Imperi. « Pseudomonas aeruginosa LptE is crucial for LptD assembly, cell envelope integrity, antibiotic resistance and virulence ». Virulence 9, n^o 1 (4 novembre 2018) : 1718–33. http://dx.doi.org/10.1080/21505594.2018.1537730.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

48

Fuchigami, Helio Yochihiro, et João Vitor Moccellin. « Efeitos de regras de prioridade para programação da produção em sistemas industriais complexos ». Revista Produção Online 16, n^o 1 (15 mars 2016) : 3. http://dx.doi.org/10.14488/1676-1901.v16i1.1720.

Texte intégral

Résumé :

Neste artigo foi discutida a eficiência da utilização de regras de prioridade para programação de sistemas produtivos conhecidos como flexible flow line com tempos de setup dependentes da sequência de processamento das tarefas. Este ambiente é caracterizado pela presença de múltiplas máquinas idênticas em cada estágio e a da possibilidade das tarefas saltarem um ou mais estágios de produção. Foram considerados tanto tempos de setup antecipados como não antecipados. O objetivo do problema foi a minimização da duração total da programação (makespan). Este estudo pode ser classificado como “pesquisa aplicada” quanto à natureza, “pesquisa exploratória” quanto aos objetivos e “pesquisa experimental” quanto aos procedimentos, além da abordagem “quantitativa”. Os resultados foram analisados por meio da porcentagem de sucesso, desvio relativo, desvio-padrão do desvio relativo e tempo de computação. As duas regras que obtiveram os melhores desempenhos foram a LPT3 e a LPT5, as únicas que consideram a ordenação decrescente da carga de trabalho em todos os estágios, ou seja, no sistema produtivo tratado é mais vantajoso priorizar as tarefas com as maiores cargas de trabalho.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Liang, Xiaofei, Ramesh Gopalaswamy, Frank Navas, Eric J. Toone et Pei Zhou. « A Scalable Synthesis of the Difluoromethyl-allo-threonyl Hydroxamate-Based LpxC Inhibitor LPC-058 ». Journal of Organic Chemistry 81, n^o 10 (6 mai 2016) : 4393–98. http://dx.doi.org/10.1021/acs.joc.6b00589.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

50

Lundstedt, Emily A., Brent W. Simpson et Natividad Ruiz. « LptB‐LptF coupling mediates the closure of the substrate‐binding cavity in the LptB 2 FGC transporter through a rigid‐body mechanism to extract LPS ». Molecular Microbiology 114, n^o 2 (14 avril 2020) : 200–213. http://dx.doi.org/10.1111/mmi.14506.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « LptC »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres