Journal articles: 'Lsr2'

1

Gordon, Blair R. G., Robin Imperial, Linru Wang, William Wiley Navarre, and Jun Liu. "Lsr2 of Mycobacterium Represents a Novel Class of H-NS-Like Proteins." Journal of Bacteriology 190, no. 21 (September 5, 2008): 7052–59. http://dx.doi.org/10.1128/jb.00733-08.

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ABSTRACT Lsr2 is a small, basic protein present in Mycobacterium and related actinomycetes. Our previous in vitro biochemical studies showed that Lsr2 is a DNA-bridging protein, a property shared by H-NS-like proteins in gram-negative bacteria. Here we present in vivo evidence based on genetic complementation experiments that Lsr2 is a functional analog of H-NS, the first such protein identified in gram-positive bacteria. We show that lsr2 can complement the phenotypes related to hns mutations in Escherichia coli, including β-glucoside utilization, mucoidy, motility, and hemolytic activity. We also show that Lsr2 binds specifically to H-NS-regulated genes and the repression of hlyE by Lsr2 can be partially eliminated by overexpression of slyA, suggesting that the molecular mechanisms of Lsr2 repression and depression are similar to those of H-NS. The functional equivalence of these two proteins is further supported by the ability of hns to complement the lsr2 phenotype in Mycobacterium smegmatis. Taken together, our results demonstrate unequivocally that Lsr2 is an H-NS-like protein.

2

Saini, Chaman, H. K. Prasad, Rajni Rani, A. Murtaza, Namita Misra, N. P. Shanker Narayan, and Indira Nath. "Lsr2 of Mycobacterium leprae and Its Synthetic Peptides Elicit Restitution of T Cell Responses in Erythema Nodosum Leprosum and Reversal Reactions in Patients with Lepromatous Leprosy." Clinical and Vaccine Immunology 20, no. 5 (February 27, 2013): 673–82. http://dx.doi.org/10.1128/cvi.00762-12.

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ABSTRACTThe Lsr2 protein ofMycobacterium lepraeand its synthetic peptides have been shown to elicit lymphoproliferation and gamma interferon (IFN-γ) release by peripheral blood mononuclear cells (PBMCs) of patients with lepromatous leprosy (M. Chaduvula, A. Murtaza, N. Misra, N. P. Narayan, V. Ramesh, H. K. Prasad, R. Rani, R. K. Chinnadurai, I. Nath, Infect. Immun. 80:742–752, 2012). PBMCs from 16 patients with lepromatous leprosy who were undergoing erythema nodosum leprosum (ENL) (type 2) and 5 patients with reversal reactions (RR) (type 1) were stimulated withM. leprae, recombinant Lsr2, and six end-to-end synthetic peptides (A through F) spanning the Lsr2 sequence. During the reaction all patients with ENL showed lymphoproliferation (stimulation index, >2) in response to peptides A and F, with other peptides eliciting responses in 75 to 88% of the subjects. In PBMC cultures, both lymphoproliferation and IFN-γ release for peptide E were significantly higher than for peptides B and C and recombinant Lsr2 (P< 0.05, Wilcoxon signed-rank test). Five patients with RR also showed enhanced lymphoproliferative responses and IFN-γ release in response to Lsr2,M. leprae, and peptide E. Six months postreaction, 14 patients with ENL continued to exhibit responses to Lsr2 and its peptides, with the highest responses being elicited by peptide E. However, 5 subjects showed no lymphoproliferation and had reduced IFN-γ release in response to Lsr2 peptides (P< 0.001, Kruskal-Wallis test) but responded to recombinant Lsr2. Six patients with ENL had HLA-A*68.01, which the STFPEITHI program showed to have high peptide-binding scores of 20 to 21 for peptides E, B, and C. Eleven patients had HLA-DRB1*1501 and HLA-DRB1*1502, which had high binding scores for peptides C and E. Thus, Lsr2 and its peptides are recognized in leprosy reactions during and well after the subsidence of clinical signs.

3

Pinault, Lucile, Jeong-Sun Han, Choong-Min Kang, Jimmy Franco, and Donald R. Ronning. "Zafirlukast Inhibits Complexation of Lsr2 with DNA and Growth of Mycobacterium tuberculosis." Antimicrobial Agents and Chemotherapy 57, no. 5 (February 25, 2013): 2134–40. http://dx.doi.org/10.1128/aac.02407-12.

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ABSTRACTThe mycobacterial nucleoid-associated protein Lsr2 is a DNA-bridging protein that plays a role in condensation and structural organization of the genome and acts as a global repressor of gene transcription. Here we describe experiments demonstrating that zafirlukast inhibits the complexation between Lsr2 and DNAin vitro. Zafirlukast is shown to inhibit growth in two different species of mycobacteria tested but exhibits no growth inhibition ofEscherichia coli. The Lsr2 inhibitory activity is reflectedin vivoas determined by monitoring of transcription levels inMycobacterium tuberculosis. These data suggest that zafirlukast inhibits Lsr2 functionin vivo, promoting dysregulation of the expression of an array of genes typically bound by Lsr2 and hindering growth. Since zafirlukast likely operates by a mechanism distinct from currentM. tuberculosisdrugs and is currently used as a prophylactic treatment for asthma, it offers an intriguing lead for development of new treatments for tuberculosis.

4

Chen, Jeffrey M., Greg J. German, David C. Alexander, Huiping Ren, Tracy Tan, and Jun Liu. "Roles of Lsr2 in Colony Morphology and Biofilm Formation of Mycobacterium smegmatis." Journal of Bacteriology 188, no. 2 (January 15, 2006): 633–41. http://dx.doi.org/10.1128/jb.188.2.633-641.2006.

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ABSTRACT The lipid-rich cell wall is a defining feature of Mycobacterium species. Individual cell wall components affect diverse mycobacterial phenotypes including colony morphology, biofilm formation, antibiotic resistance, and virulence. In this study, we describe a transposon insertion mutant of Mycobacterium smegmatis mc2155 that exhibits altered colony morphology and defects in biofilm formation. The mutation was localized to the lsr2 gene. First identified as an immunodominant T-cell antigen of Mycobacterium leprae, lsr2 orthologs have been identified in all sequenced mycobacterial genomes, and homologs are found in many actinomycetes. Although its precise function remains unknown, localization experiments indicate that Lsr2 is a cytosolic protein, and cross-linking experiments demonstrate that it exists as a dimer. Characterization of cell wall lipid components reveals that the M. smegmatis lsr2 mutant lacks two previously unidentified apolar lipids. Characterization by mass spectrometry and thin-layer chromatography indicate that these two apolar lipids are novel mycolate-containing compounds, called mycolyl-diacylglycerols (MDAGs), in which a mycolic acid (α- or α′-mycolate) molecule is esterified to a glycerol. Upon complementation with an intact lsr2 gene, the mutant reverts to the parental phenotypes and MDAG production is restored. This study demonstrates that due to its impact on the biosynthesis of the hydrophobic MDAGs, Lsr2 plays an important role in the colony morphology and biofilm formation of M. smegmatis.

5

Arora, Kriti, Danelle C. Whiteford, Dalia Lau-Bonilla, Christine M. Davitt, and John L. Dahl. "Inactivation of lsr2 Results in a Hypermotile Phenotype in Mycobacterium smegmatis." Journal of Bacteriology 190, no. 12 (April 11, 2008): 4291–300. http://dx.doi.org/10.1128/jb.00023-08.

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ABSTRACT Mycobacterial species are characterized by the presence of lipid-rich, hydrophobic cell envelopes. These cell envelopes contribute to properties such as roughness of colonies, aggregation of cells in liquid culture without detergent, and biofilm formation. We describe here a mutant strain of Mycobacterium smegmatis, called DL1215, which demonstrates marked deviations from the above-mentioned phenotypes. DL1215 arose spontaneously from a strain deficient for the stringent response (M. smegmatis ΔrelMsm strain) and is not a reversion to a wild-type phenotype. The nature of the spontaneous mutation was a single base-pair deletion in the lsr2 gene, leading to the formation of a truncated protein product. The DL1215 strain was complicated by having both inactivated relMsm and lsr2 genes, and so a single lsr2 mutant was created to analyze the gene's function. The lsr2 gene was inactivated in the wild-type M. smegmatis mc2155 strain by allelic replacement to create strain DL2008. Strain DL2008 shows characteristics unique from those of both the wild-type and ΔrelMsm strains, some of which include a greatly enhanced ability to slide over agar surfaces (referred to here as “hypermotility”), greater resistance to phage infection and to the antibiotic kanamycin, and an inability to form biofilms. Complementation of the DL2008 mutant with a plasmid containing lsr2 (pLSR2) reverts the strain to the mc2155 phenotype. Although these phenotypic differences allude to changes in cell surface lipids, no difference is observed in glycopeptidolipids, polar lipids, apolar lipids, or mycolic acids of the cell wall.

6

Seo, Jeong-Woo, Ki-Hyo Jang, Soon Ah Kang, Ki-Bang Song, Eun Kyung Jang, Buem-Seek Park, Chul Ho Kim, and Sang-Ki Rhee. "Molecular Characterization of the Growth Phase-Dependent Expression of the lsrA Gene, Encoding Levansucrase of Rahnella aquatilis." Journal of Bacteriology 184, no. 21 (November 1, 2002): 5862–70. http://dx.doi.org/10.1128/jb.184.21.5862-5870.2002.

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ABSTRACT Expression of the lsrA gene from Rahnella aquatilis, encoding levansucrase, is tightly regulated by the growth phase of the host cell; low-level expression was observed in the early phase of cell growth, but expression was significantly stimulated in the late phase. Northern blot analysis revealed that regulation occurred at the level of transcription. The promoter region was identified by primer extension analysis. Two opposite genetic elements that participate in the regulation of lsrA expression were identified upstream of the lsrA gene: the lsrS gene and the lsrR region. The lsrS gene encodes a protein consisting of 70 amino acid residues (M r, 8,075), which positively activated lsrA expression approximately 20-fold in a growth phase-dependent fashion. The cis-acting lsrR region, which repressed lsrA expression about 10-fold, was further narrowed to two DNA regions by deletion analysis. The concerted action of two opposite regulatory functions resulted in the growth phase-dependent activation of gene expression in Escherichia coli independent of the stationary sigma factor σS.

7

Gerges, Elias, Jean-Louis Herrmann, and Frédéric Crémazy. "Lsr2 : protéine associée au nucléoïde (NAP) et facteur transcriptionnel chez les mycobactéries." médecine/sciences 40, no. 2 (February 2024): 154–60. http://dx.doi.org/10.1051/medsci/2023218.

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Lsr2, une petite protéine conservée chez les actinobactéries, joue un rôle crucial dans la virulence et l’adaptation des mycobactéries aux conditions environnementales. Membre de la superfamille des protéines associées au nucléoïde (NAP), Lsr2 influence l’organisation de l’ADN en facilitant la formation de boucle chromosomique in vitro, ce qui suggère qu’elle pourrait être un acteur majeur du repliement tridimensionnel du génome. Lsr2 agit également comme un facteur de transcription, régulant l’expression de nombreux gènes responsables de la coordination d’une multitude de processus cellulaires et moléculaires essentiels chez les actinobactéries. Tout comme la protéine H-NS, son orthologue chez les entérobactéries, son rôle de répresseur transcriptionnel repose probablement sur son oligomérisation conduisant à la rigidification de l’ADN et, dans certaines situations, sur le pontage de fragments génomiques distants. Ces mécanismes pourraient perturber le recrutement de l’ARN polymérase sur les promoteurs ainsi que l’élongation des transcrits.

8

Li, Yakun, Yuyun Wei, Xiao Guo, Xiaohui Li, Lining Lu, Lihua Hu, and Zheng‐Guo He. "Insertion sequence transposition activates antimycobacteriophage immunity through an lsr2‐silenced lipid metabolism gene island." mLife 3, no. 1 (March 2024): 87–100. http://dx.doi.org/10.1002/mlf2.12106.

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AbstractInsertion sequences (ISs) exist widely in bacterial genomes, but their roles in the evolution of bacterial antiphage defense remain to be clarified. Here, we report that, under the pressure of phage infection, the IS1096 transposition of Mycobacterium smegmatis into the lsr2 gene can occur at high frequencies, which endows the mutant mycobacterium with a broad‐spectrum antiphage ability. Lsr2 functions as a negative regulator and directly silences expression of a gene island composed of 11 lipid metabolism‐related genes. The complete or partial loss of the gene island leads to a significant decrease of bacteriophage adsorption to the mycobacterium, thus defending against phage infection. Strikingly, a phage that has evolved mutations in two tail‐filament genes can re‐escape from the lsr2 inactivation‐triggered host defense. This study uncovered a new signaling pathway for activating antimycobacteriophage immunity by IS transposition and provided insight into the natural evolution of bacterial antiphage defense.

9

Nguyen, Kiet T., Kristina Piastro, Todd A. Gray, and Keith M. Derbyshire. "Mycobacterial Biofilms Facilitate Horizontal DNA Transfer between Strains of Mycobacterium smegmatis." Journal of Bacteriology 192, no. 19 (July 30, 2010): 5134–42. http://dx.doi.org/10.1128/jb.00650-10.

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ABSTRACT Conjugal transfer of chromosomal DNA between strains of Mycobacterium smegmatis occurs by a novel mechanism. In a transposon mutagenesis screen, three transfer-defective insertions were mapped to the lsr2 gene of the donor strain mc2155. Because lsr2 encodes a nonspecific DNA-binding protein, mutations of lsr2 give rise to a variety of phenotypes, including an inability to form biofilms. In this study, we show that efficient DNA transfer between strains of M. smegmatis occurs in a mixed biofilm and that the process requires expression of lsr2 in the donor but not in the recipient strain. Testing cells from different strata of standing cultures showed that transfer occurred predominantly at the biofilm air-liquid interface, as other strata containing higher cell densities produced very few transconjugants. These data suggest that the biofilm plays a role beyond mere facilitation of cell-cell contact. Surprisingly, we found that under standard assay conditions the recipient strain does not form a biofilm. Taking these results together, we conclude that for transfer to occur, the recipient strain is actively recruited into the biofilm. In support of this idea, we show that donor and recipient cells are present in almost equal numbers in biofilms that produce transconjugants. Our demonstration of genetic exchange between mycobacteria in a mixed biofilm suggests that conjugation occurs in the environment. Since biofilms are considered to be the predominant natural microhabitat for bacteria, our finding emphasizes the importance of studying biological and physical processes that occur between cells in mixed biofilms.

10

Deng, Lina, Rui Wang, Guowei Wang, Mingxu Liu, Guojian Liao, Zhihua Liao, and Min Chen. "Targeted isolation of sulfur-containing metabolites from Lsr2-deletion mutant strain of Streptomyces roseosporus." RSC Advances 7, no. 60 (2017): 37771–77. http://dx.doi.org/10.1039/c7ra06482a.

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11

Chaduvula, Mehervani, A. Murtaza, Namita Misra, N. P. Shankar Narayan, V. Ramesh, H. K. Prasad, Rajni Rani, R. K. Chinnadurai, and Indira Nath. "Lsr2 Peptides of Mycobacterium leprae Show Hierarchical Responses in Lymphoproliferative Assays, with Selective Recognition by Patients with Anergic Lepromatous Leprosy." Infection and Immunity 80, no. 2 (December 5, 2011): 742–52. http://dx.doi.org/10.1128/iai.05384-11.

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ABSTRACTLsr2 protein ofMycobacterium lepraewas shown earlier to elicit B and T cell responses in leprosy patients (20, 28). Lymphoproliferation toM. lepraeand Lsr2 antigens was observed in >70% of tuberculoid (T) patients and in 16 and 34% of lepromatous (L) patients, respectively. We focused on theM. lepraenonresponders in the lepromatous group using 22 synthetic Lsr2 peptides (end-to-end peptides A to F and overlapping peptides p1 to p16) inin vitroT cell responses. A total of 125 leprosy and 13 tuberculosis patients and 19 healthy controls from the area of endemicity (here, healthy controls, or HC) were investigated. The highest responses were observed (67 to 100%) in HC for all peptides except p1 to p3, and the lowest was observed in tuberculosis patients. Significant differences in lymphoproliferation were observed in T, L, and HC groups (analysis of variance [ANOVA],P= 0.000 to 0.015) for all end-to-end peptides except B and for p5 and p7 to p10. Hierarchical recognition between lepromatous and tuberculoid leprosy was noted for p8 (P< 0.05) and between the HC and L groups for p7 to p10, p15, and p16 (P< 0.005 toP< 0.02). Significant lymphoproliferation was observed to peptides A to F and p1 to p9, p11, p12, p15, p16 (P= 0.000 to 0.001) with 40% responding to peptides C and p16 in L patients. Lepromatous patients also showed significantly higher levels of a gamma interferon (IFN-γ) response to peptide C than to other peptides (P< 0.05). Major histocompatibility complex (MHC) class II bias for peptide recognition was not observed. These studies indicate that Lsr2 has multiple T cell epitopes that inducein vitroT cell responses in the highly infective lepromatous leprosy patients.

12

Qu, Yuanyuan, Ci Ji Lim, Yixun R. Whang, Jun Liu, and Jie Yan. "Mechanism of DNA organization by Mycobacterium tuberculosis protein Lsr2." Nucleic Acids Research 41, no. 10 (April 10, 2013): 5263–72. http://dx.doi.org/10.1093/nar/gkt249.

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Chen, Jeffrey M., Huiping Ren, James E. Shaw, Yu Jing Wang, Ming Li, Andrea S. Leung, Vanessa Tran, et al. "Lsr2 of Mycobacterium tuberculosis is a DNA-bridging protein." Nucleic Acids Research 36, no. 7 (January 10, 2008): 2123–35. http://dx.doi.org/10.1093/nar/gkm1162.

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Li, Jun, Can Attila, Liang Wang, Thomas K. Wood, James J. Valdes, and William E. Bentley. "Quorum Sensing in Escherichia coli Is Signaled by AI-2/LsrR: Effects on Small RNA and Biofilm Architecture." Journal of Bacteriology 189, no. 16 (June 8, 2007): 6011–20. http://dx.doi.org/10.1128/jb.00014-07.

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ABSTRACT The regulatory network for the uptake of Escherichia coli autoinducer 2 (AI-2) is comprised of a transporter complex, LsrABCD; its repressor, LsrR; and a cognate signal kinase, LsrK. This network is an integral part of the AI-2 quorum-sensing (QS) system. Because LsrR and LsrK directly regulate AI-2 uptake, we hypothesized that they might play a wider role in regulating other QS-related cellular functions. In this study, we characterized physiological changes due to the genomic deletion of lsrR and lsrK. We discovered that many genes were coregulated by lsrK and lsrR but in a distinctly different manner than that for the lsr operon (where LsrR serves as a repressor that is derepressed by the binding of phospho-AI-2 to the LsrR protein). An extended model for AI-2 signaling that is consistent with all current data on AI-2, LuxS, and the LuxS regulon is proposed. Additionally, we found that both the quantity and architecture of biofilms were regulated by this distinct mechanism, as lsrK and lsrR knockouts behaved identically. Similar biofilm architectures probably resulted from the concerted response of a set of genes including flu and wza, the expression of which is influenced by lsrRK. We also found for the first time that the generation of several small RNAs (including DsrA, which was previously linked to QS systems in Vibrio harveyi) was affected by LsrR. Our results suggest that AI-2 is indeed a QS signal in E. coli, especially when it acts through the transcriptional regulator LsrR.

15

Custodio, Luiz Antonio, Alexandre Saito, Marla Karine Amarante, Thiago Cezar Fujita, Aparecida de Lourdes Perim, Ivete Conchon Costa, Ionice Felipe, and Shiduca Itow Jankevicius. "Detection of Lsr2 gene of Mycobacterium leprae in nasal mucus." Brazilian Archives of Biology and Technology 55, no. 3 (June 2012): 375–80. http://dx.doi.org/10.1590/s1516-89132012000300007.

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Yang, Wenfeng, Pengyi Li, Wei Yang, Yuxing Liu, Yulong He, Ovanes Petrosian, and Aleksandr Davydenko. "Research on Robust Audio-Visual Speech Recognition Algorithms." Mathematics 11, no. 7 (April 5, 2023): 1733. http://dx.doi.org/10.3390/math11071733.

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Automatic speech recognition (ASR) that relies on audio input suffers from significant degradation in noisy conditions and is particularly vulnerable to speech interference. However, video recordings of speech capture both visual and audio signals, providing a potent source of information for training speech models. Audiovisual speech recognition (AVSR) systems enhance the robustness of ASR by incorporating visual information from lip movements and associated sound production in addition to the auditory input. There are many audiovisual speech recognition models and systems for speech transcription, but most of them have been tested based in a single experimental setting and with a limited dataset. However, a good model should be applicable to any scenario. Our main contributions are: (i) Reproducing the three best-performing audiovisual speech recognition models in the current AVSR research area using the most famous audiovisual databases, LSR2 (Lip Reading Sentences 2) LSR3 (Lip Reading Sentences 3), and comparing and analyzing their performances under various noise conditions. (ii) Based on our experimental and research experiences, we analyzed the problems currently encountered in the AVSR domain, which are summarized as the feature-extraction problem and the domain-generalization problem. (iii) According to the experimental results, the Moco (momentum contrast) + word2vec (word to vector) model has the best AVSR effect on the LRS datasets regardless of whether there is noise or not. Additionally, the model also produced the best experimental results in the experiments of audio recognition and video recognition. Our research lays the foundation for further improving the performance of AVSR models.

17

Ha, Jung-Hye, Yumi Eo, Hee-Chul Ahn, and Kyoung-Seok Ryu. "Increasing the soluble expression and crystallization of theEscherichia coliquorum-sensing protein LsrK." Acta Crystallographica Section F Structural Biology Communications 73, no. 5 (April 26, 2017): 253–58. http://dx.doi.org/10.1107/s2053230x1700468x.

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LsrK is one of the key components of theluxS-regulated (lsr) operon inEscherichia coliand plays an important role during the quorum-sensing (QS) process mediated by autoinducer-2 (AI-2). The AI-2 molecule is imported into the cell by the LsrACB transporter and is subsequently phosphorylated (to AI-2-P) by LsrK. AI-2-P binds to the repressor protein of thelsroperon (LsrR) and triggers various cellular responses related to QS by dissociating LsrR from the DNA. Although a large amount of purified LsrK is required for structural studies, recombinant GST-LsrK was mostly expressed in an insoluble form. To enhance the soluble expression of LsrK, an attempt was made to increase the expression of the cellular chaperone proteins that are well known to support proper protein folding. TransformedE. coliwas cultured in high-salt LB medium and heat shock was applied prior to subsequent IPTG induction at 20°C. These procedures increased the yield of purified LsrK by about tenfold compared with standard IPTG induction at 20°C. The expressed LsrK was readily purified by GST-affinity chromatography. Crystals of LsrK were grown by the hanging-drop vapour-diffusion method. The X-ray diffraction data of the crystal were processed in a primitive hexagonal space group to 2.9 Å resolution.

18

Colangeli, R., A. Haq, V. L. Arcus, E. Summers, R. S. Magliozzo, A. McBride, A. K. Mitra, et al. "The multifunctional histone-like protein Lsr2 protects mycobacteria against reactive oxygen intermediates." Proceedings of the National Academy of Sciences 106, no. 11 (February 23, 2009): 4414–18. http://dx.doi.org/10.1073/pnas.0810126106.

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Ashmead, Helen M., Leonardo Negron, Kyle Webster, Vic Arcus, and Juliet A. Gerrard. "Proteins as supramolecular building blocks: Nterm-Lsr2 as a new protein tecton." Biopolymers 103, no. 5 (February 21, 2015): 260–70. http://dx.doi.org/10.1002/bip.22592.

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Wang, Liang, Jun Li, John C. March, James J. Valdes, and William E. Bentley. "luxS-Dependent Gene Regulation in Escherichia coli K-12 Revealed by Genomic Expression Profiling." Journal of Bacteriology 187, no. 24 (December 15, 2005): 8350–60. http://dx.doi.org/10.1128/jb.187.24.8350-8360.2005.

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ABSTRACT The bacterial quorum-sensing autoinducer 2 (AI-2) has received intense interest because the gene for its synthase, luxS, is common among a large number of bacterial species. We have identified luxS-controlled genes in Escherichia coli under two different growth conditions using DNA microarrays. Twenty-three genes were affected by luxS deletion in the presence of glucose, and 63 genes were influenced by luxS deletion in the absence of glucose. Minimal overlap among these gene sets suggests the role of luxS is condition dependent. Under the latter condition, the metE gene, the lsrACDBFG operon, and the flanking genes of the lsr operon (lsrR, lsrK, tam, and yneE) were among the most significantly induced genes by luxS. The E. coli lsr operon includes an additional gene, tam, encoding an S-adenosyl-l-methionine-dependent methyltransferase. Also, lsrR and lsrK belong to the same operon, lsrRK, which is positively regulated by the cyclic AMP receptor protein and negatively regulated by LsrR. lsrK is additionally transcribed by a promoter between lsrR and lsrK. Deletion of luxS was also shown to affect genes involved in methionine biosynthesis, methyl transfer reactions, iron uptake, and utilization of carbon. It was surprising, however, that so few genes were affected by luxS deletion in this E. coli K-12 strain under these conditions. Most of the highly induced genes are related to AI-2 production and transport. These data are consistent with the function of LuxS as an important metabolic enzyme but appear not to support the role of AI-2 as a true signal molecule for E. coli W3110 under the investigated conditions.

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Han, Hui, Kaijie Zhang, Guoxiong Li, Ying Yu, Shuqi Shi, Caice Liang, Huanqing Niu, et al. "Autoinducer-2: Its Role in Biofilm Formation and L-Threonine Production in Escherichia coli." Fermentation 9, no. 10 (October 19, 2023): 916. http://dx.doi.org/10.3390/fermentation9100916.

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Biofilms enable bacterial cells to adhere and thrive on surfaces, with associated changes in growth and gene expression aiding their survival in challenging environments. While previous research has explored E. coli biofilm formation, there has been limited exploration of its application in industrial production. Prior studies have shown that immobilized fermentation can enhance L-threonine production. This study aims to augment biofilm formation and subsequently increase L-threonine production in E. coli by regulating the quorum sensing system, focusing on key AI-2-related genes, including luxS, lsrB, lsrK, and lsrR. In +pluxS and +plsrB strains, AI-2 levels were significantly altered, resulting in enhanced biofilm formation, increased curli expression, shorter free-cell fermentation periods, and improved production efficiency through immobilized continuous fermentation. In a single batch of free-cell fermentation with E. coli W1688, L-threonine production was 10.16 g/L. However, +pluxS and +plsrB strains achieved L-threonine yields of 15.27 g/L and 13.38 g/L, respectively, after seven fermentation batches. Additionally, the fermentation period was reduced from 36 h to 28 h and 30 h, respectively.

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Kurthkoti, Krishna, Priyanka Tare, Rakhi Paitchowdhury, Vykuntham Naga Gowthami, Maria J. Garcia, Roberto Colangeli, Dipankar Chatterji, Valakunja Nagaraja, and G. Marcela Rodriguez. "The mycobacterial iron-dependent regulator IdeR induces ferritin (bfrB) by alleviating Lsr2 repression." Molecular Microbiology 98, no. 5 (September 18, 2015): 864–77. http://dx.doi.org/10.1111/mmi.13166.

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Gopal-Srivastava, Rashmi, Ales Cvekl, and Joram Piatigorsky. "Pax-6 and αB-crystallin/Small Heat Shock Protein Gene Regulation in the Murine Lens INTERACTION WITH THE LENS-SPECIFIC REGIONS, LSR1 AND LSR2." Journal of Biological Chemistry 271, no. 38 (September 20, 1996): 23029–36. http://dx.doi.org/10.1074/jbc.271.38.23029.

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Liu, Jun, and Blair RG Gordon. "Targeting the global regulator Lsr2 as a novel approach for anti-tuberculosis drug development." Expert Review of Anti-infective Therapy 10, no. 9 (September 2012): 1049–53. http://dx.doi.org/10.1586/eri.12.86.

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Bai, Yubin, Weiwei Wang, Mengyan Shi, Xiaojuan Wei, Xuzheng Zhou, Bing Li, and Jiyu Zhang. "Novel Antibiofilm Inhibitor Ginkgetin as an Antibacterial Synergist against Escherichia coli." International Journal of Molecular Sciences 23, no. 15 (August 8, 2022): 8809. http://dx.doi.org/10.3390/ijms23158809.

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As an opportunistic pathogen, Escherichia coli (E. coli) forms biofilm that increases the virulence of bacteria and antibiotic resistance, posing a serious threat to human and animal health. Recently, ginkgetin (Gin) has been discovered to have antiinflammatory, antioxidant, and antitumor properties. In the present study, we evaluated the antibiofilm and antibacterial synergist of Gin against E. coli. Additionally, Alamar Blue assay combined with confocal laser scanning microscope (CLSM) and crystal violet (CV) staining was used to evaluate the effect of antibiofilm and antibacterial synergist against E. coli. Results showed that Gin reduces biofilm formation, exopolysaccharide (EPS) production, and motility against E. coli without limiting its growth and metabolic activity. Furthermore, we identified the inhibitory effect of Gin on AI-2 signaling molecule production, which showed apparent anti-quorum sensing (QS) properties. The qRT-PCR also indicated that Gin reduced the transcription of curli-related genes (csgA, csgD), flagella-formation genes (flhC, flhD, fliC, fliM), and QS-related genes (luxS, lsrB, lsrK, lsrR). Moreover, Gin showed obvious antibacterial synergism to overcome antibiotic resistance in E. coli with marketed antibiotics, including gentamicin, colistin B, and colistin E. These results suggested the potent antibiofilm and novel antibacterial synergist effect of Gin for treating E. coli infections.

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Park, Kun Taek, John L. Dahl, John P. Bannantine, Raúl G. Barletta, Jongsam Ahn, Andrew J. Allen, Mary Jo Hamilton, and William C. Davis. "Demonstration of Allelic Exchange in the Slow-Growing Bacterium Mycobacterium avium subsp. paratuberculosis, and Generation of Mutants with Deletions at the pknG, relA, and lsr2 Loci." Applied and Environmental Microbiology 74, no. 6 (January 11, 2008): 1687–95. http://dx.doi.org/10.1128/aem.01208-07.

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ABSTRACT Mycobacterium avium subsp. paratuberculosis is the causative pathogen of Johne's disease, a chronic inflammatory wasting disease in ruminants. This disease has been difficult to control because of the lack of an effective vaccine. To address this need, we adapted a specialized transduction system originally developed for M. tuberculosis and modified it to improve the efficiency of allelic exchange in order to generate site-directed mutations in preselected M. avium subsp. paratuberculosis genes. With our novel optimized method, the allelic exchange frequency was 78 to 100% and the transduction frequency was 1.1 × 10−7 to 2.9 × 10−7. Three genes were selected for mutagenesis: pknG and relA, which are genes that are known to be important virulence factors in M. tuberculosis and M. bovis, and lsr2, a gene regulating lipid biosynthesis and antibiotic resistance. Mutants were successfully generated with a virulent strain of M. avium subsp. paratuberculosis (M. avium subsp. paratuberculosis K10) and with a recombinant K10 strain expressing the green fluorescent protein gene, gfp. The improved efficiency of disruption of selected genes in M. avium subsp. paratuberculosis should accelerate development of additional mutants for vaccine testing and functional studies.

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Qin, L., A. M. Erkelens, F. Ben Bdira, and R. T. Dame. "The architects of bacterial DNA bridges: a structurally and functionally conserved family of proteins." Open Biology 9, no. 12 (December 2019): 190223. http://dx.doi.org/10.1098/rsob.190223.

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Every organism across the tree of life compacts and organizes its genome with architectural chromatin proteins. While eukaryotes and archaea express histone proteins, the organization of bacterial chromosomes is dependent on nucleoid-associated proteins. In Escherichia coli and other proteobacteria, the histone-like nucleoid structuring protein (H-NS) acts as a global genome organizer and gene regulator. Functional analogues of H-NS have been found in other bacterial species: MvaT in Pseudomonas species, Lsr2 in actinomycetes and Rok in Bacillus species. These proteins complement hns − phenotypes and have similar DNA-binding properties, despite their lack of sequence homology. In this review, we focus on the structural and functional characteristics of these four architectural proteins. They are able to bridge DNA duplexes, which is key to genome compaction, gene regulation and their response to changing conditions in the environment. Structurally the domain organization and charge distribution of these proteins are conserved, which we suggest is at the basis of their conserved environment responsive behaviour. These observations could be used to find and validate new members of this protein family and to predict their response to environmental changes.

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Gordon, B. R. G., Y. Li, L. Wang, A. Sintsova, H. van Bakel, S. Tian, W. W. Navarre, B. Xia, and J. Liu. "Lsr2 is a nucleoid-associated protein that targets AT-rich sequences and virulence genes in Mycobacterium tuberculosis." Proceedings of the National Academy of Sciences 107, no. 11 (January 20, 2010): 5154–59. http://dx.doi.org/10.1073/pnas.0913551107.

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Alqaseer, Kawther, Obolbek Turapov, Philippe Barthe, Heena Jagatia, Angélique De Visch, Christian Roumestand, Malgorzata Wegrzyn, et al. "Protein kinase B controls Mycobacterium tuberculosis growth via phosphorylation of the transcriptional regulator Lsr2 at threonine 112." Molecular Microbiology 112, no. 6 (October 10, 2019): 1847–62. http://dx.doi.org/10.1111/mmi.14398.

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Du, Yanli, Hua Zhang, Yang He, Feng Huang, and Zheng-Guo He. "Mycobacterium smegmatis Lsr2 physically and functionally interacts with a new flavoprotein involved in bacterial resistance to oxidative stress." Journal of Biochemistry 152, no. 5 (September 5, 2012): 479–86. http://dx.doi.org/10.1093/jb/mvs095.

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Datta, Chandreyee, Rajiv Kumar Jha, Wareed Ahmed, Sohini Ganguly, Soumitra Ghosh, and Valakunja Nagaraja. "Physical and functional interaction between nucleoid‐associated proteins HU and Lsr2 ofMycobacterium tuberculosis: altered DNA binding and gene regulation." Molecular Microbiology 111, no. 4 (February 11, 2019): 981–94. http://dx.doi.org/10.1111/mmi.14202.

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Summers, Emma L., Kathrin Meindl, Isabel Usón, Alok K. Mitra, Mazdak Radjainia, Roberto Colangeli, David Alland, and Vickery L. Arcus. "The Structure of the Oligomerization Domain of Lsr2 from Mycobacterium tuberculosis Reveals a Mechanism for Chromosome Organization and Protection." PLoS ONE 7, no. 6 (June 13, 2012): e38542. http://dx.doi.org/10.1371/journal.pone.0038542.

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Colangeli, Roberto, Danica Helb, Catherine Vilchèze, Manzour Hernando Hazbón, Chee-Gun Lee, Hassan Safi, Brendan Sayers, et al. "Transcriptional Regulation of Multi-Drug Tolerance and Antibiotic-Induced Responses by the Histone-Like Protein Lsr2 in M. tuberculosis." PLoS Pathogens 3, no. 6 (June 22, 2007): e87. http://dx.doi.org/10.1371/journal.ppat.0030087.

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Luo, Li, Shi-Yi Yao, Anke Becker, Silvia Rüberg, Guan-Qiao Yu, Jia-Bi Zhu, and Hai-Ping Cheng. "Two New Sinorhizobium meliloti LysR-Type Transcriptional Regulators Required for Nodulation." Journal of Bacteriology 187, no. 13 (July 1, 2005): 4562–72. http://dx.doi.org/10.1128/jb.187.13.4562-4572.2005.

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ABSTRACT The establishment of an effective nitrogen-fixing symbiosis between Sinorhizobium meliloti and its legume host alfalfa (Medicago sativa) depends on the timely expression of nodulation genes that are controlled by LysR-type regulators. Ninety putative genes coding for LysR-type transcriptional regulators were identified in the recently sequenced S. meliloti genome. All 90 putative lysR genes were mutagenized using plasmid insertions as a first step toward determining their roles in symbiosis. Two new LysR-type symbiosis regulator genes, lsrA and lsrB, were identified in the screening. Both the lsrA and lsrB genes are expressed in free-living S. meliloti cells, but they are not required for cell growth. An lsrA1 mutant was defective in symbiosis and elicited only white nodules that exhibited no nitrogenase activity. Cells of the lsrA1 mutant were recovered from the white nodules, suggesting that the lsrA1 mutant was blocked early in nodulation. An lsrB1 mutant was deficient in symbiosis and elicited a mixture of pink and white nodules on alfalfa plants. These plants exhibited lower overall nitrogenase activity than plants inoculated with the wild-type strain, which is consistent with the fact that most of the alfalfa plants inoculated with the lsrB1 mutant were short and yellow. Cells of the lsrB1 mutant were recovered from both pink and white nodules, suggesting that lsrB1 mutants could be blocked at multiple points during nodulation. The identification of two new LysR-type symbiosis transcriptional regulators provides two new avenues for understanding the complex S. meliloti-alfalfa interactions which occur during symbiosis.

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Wang, Liang, Yoshifumi Hashimoto, Chen-Yu Tsao, James J. Valdes, and William E. Bentley. "Cyclic AMP (cAMP) and cAMP Receptor Protein Influence both Synthesis and Uptake of Extracellular Autoinducer 2 in Escherichia coli." Journal of Bacteriology 187, no. 6 (March 15, 2005): 2066–76. http://dx.doi.org/10.1128/jb.187.6.2066-2076.2005.

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ABSTRACT Bacterial autoinducer 2 (AI-2) is proposed to be an interspecies mediator of cell-cell communication that enables cells to operate at the multicellular level. Many environmental stimuli have been shown to affect the extracellular AI-2 levels, carbon sources being among the most important. In this report, we show that both AI-2 synthesis and uptake in Escherichia coli are subject to catabolite repression through the cyclic AMP (cAMP)-CRP complex, which directly stimulates transcription of the lsr (for “luxS regulated”) operon and indirectly represses luxS expression. Specifically, cAMP-CRP is shown to bind to a CRP binding site located in the upstream region of the lsr promoter and works with the LsrR repressor to regulate AI-2 uptake. The functions of the lsr operon and its regulators, LsrR and LsrK, previously reported in Salmonella enterica serovar Typhimurium, are confirmed here for E. coli. The elucidation of cAMP-CRP involvement in E. coli autoinduction impacts many areas, including the growth of E. coli in fermentation processes.

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Ramakrishnan, S., M. B. Sukhaswami, K. M. Patil, and C. Eswaran. "Sequence Data Analysis Reveals a Relationship Between LSR2, the Recombinant Fusion Protein Mimicing M.Leprae and VIF of Bovine Immunodeficiency Virus (BIV)." Journal of Biomolecular Structure and Dynamics 15, no. 3 (December 1997): 605–9. http://dx.doi.org/10.1080/07391102.1997.10508970.

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Xavier, Karina B., and Bonnie L. Bassler. "Regulation of Uptake and Processing of the Quorum-Sensing Autoinducer AI-2 in Escherichia coli." Journal of Bacteriology 187, no. 1 (January 1, 2005): 238–48. http://dx.doi.org/10.1128/jb.187.1.238-248.2005.

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ABSTRACT AI-2 is a quorum-sensing signaling molecule proposed to be involved in interspecies communication. In Escherichia coli and Salmonella enterica serovar Typhimurium, extracellular AI-2 accumulates in exponential phase, but the amount decreases drastically upon entry into stationary phase. In S. enterica serovar Typhimurium, the reduction in activity is due to import and processing of AI-2 by the Lsr transporter. We show that the Lsr transporter is functional in E. coli, and screening for mutants defective in AI-2 internalization revealed lsrK and glpD. Unlike the wild type, lsrK and glpD mutants do not activate transcription of the lsr operon in response to AI-2. lsrK encodes the AI-2 kinase, and the lsrK mutant fails to activate lsr expression because it cannot produce phospho-AI-2, which is the lsr operon inducer. glpD encodes the glycerol-3-phosphate (G3P) dehydrogenase, which is involved in glycerol and G3P metabolism. G3P accumulates in the glpD mutant and represses lsr transcription by preventing cyclic AMP (cAMP)-catabolite activator protein (CAP)-dependent activation. Dihydroxyacetone phosphate (DHAP) also accumulates in the glpD mutant, and DHAP represses lsr transcription by a cAMP-CAP-independent mechanism involving LsrR, the lsr operon repressor. The requirement for cAMP-CAP in lsr activation explains why AI-2 persists in culture fluids of bacteria grown in media containing sugars that cause catabolite repression. These findings show that, depending on the prevailing growth conditions, the amount of time that the AI-2 signal is present and, in turn, the time that a given community of bacteria remains exposed to this signal can vary greatly.

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Báez-Ramírez, Estalina, Luis Querales, Carlos Andres Aranaga, Gustavo López, Elba Guerrero, Laurent Kremer, Séverine Carrère-Kremer, et al. "Elimination of PknL and MSMEG_4242 in Mycobacterium smegmatis alters the character of the outer cell envelope and selects for mutations in Lsr2." Cell Surface 7 (December 2021): 100060. http://dx.doi.org/10.1016/j.tcsw.2021.100060.

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Janczarek, Monika. "The Ros/MucR Zinc-Finger Protein Family in Bacteria: Structure and Functions." International Journal of Molecular Sciences 23, no. 24 (December 8, 2022): 15536. http://dx.doi.org/10.3390/ijms232415536.

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Ros/MucR is a widespread family of bacterial zinc-finger-containing proteins that integrate multiple functions, such as symbiosis, virulence, transcription regulation, motility, production of surface components, and various other physiological processes in cells. This regulatory protein family is conserved in bacteria and is characterized by its zinc-finger motif, which has been proposed as the ancestral domain from which the eukaryotic C2H2 zinc-finger structure has evolved. The first prokaryotic zinc-finger domain found in the transcription regulator Ros was identified in Agrobacterium tumefaciens. In the past decades, a large body of evidence revealed Ros/MucR as pleiotropic transcriptional regulators that mainly act as repressors through oligomerization and binding to AT-rich target promoters. The N-terminal domain and the zinc-finger-bearing C-terminal region of these regulatory proteins are engaged in oligomerization and DNA binding, respectively. These properties of the Ros/MucR proteins are similar to those of xenogeneic silencers, such as H-NS, MvaT, and Lsr2, which are mainly found in other lineages. In fact, a novel functional model recently proposed for this protein family suggests that they act as H-NS-‘like’ gene silencers. The prokaryotic zinc-finger domain exhibits interesting structural and functional features that are different from that of its eukaryotic counterpart (a βββα topology), as it folds in a significantly larger zinc-binding globular domain (a βββαα topology). Phylogenetic analysis of Ros/MucR homologs suggests an ancestral origin of this type of protein in α-Proteobacteria. Furthermore, multiple duplications and lateral gene transfer events contributing to the diversity and phyletic distribution of these regulatory proteins were found in bacterial genomes.

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Bruni, Gillian O., Yunci Qi, Evan Terrell, Rebecca A. Dupre, and Christopher P. Mattison. "Characterization of Levan Fructan Produced by a Gluconobacter japonicus Strain Isolated from a Sugarcane Processing Facility." Microorganisms 12, no. 1 (January 5, 2024): 107. http://dx.doi.org/10.3390/microorganisms12010107.

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During raw sugarcane processing, a significant portion of lost sucrose is attributable to microbial degradation. Sucrose consumption by many bacteria is also linked to the production of exopolysaccharides (EPS) such as dextrans and fructans. These resulting EPS cause operational challenges during raw sugar manufacturing. Here, we report the characterization of EPS from a fructan-forming Gluconobacter japonicus bacterium that we previously isolated from a Louisiana sugarcane factory. The genome sequencing revealed the presence of two encoded levansucrase genes, lsrA and lsrB. One levansucrase, LsrB, was detected in the secreted protein fraction of G. japonicus LASM12 by QTOF LC-MS. The spotting assays indicated that G. japonicus produces EPS using sucrose and raffinose as substrates. The G. japonicus EPS correlated with levan fructan commercial standards by 1H-NMR, and with the characteristic carbohydrate fingerprint region for FTIR spectra, confirming that the G. japonicus EPS is levan fructan. The glycosyl composition and glycosyl linkage analysis revealed a linear β-2,6-fructofuranosyl polysaccharide with occasional (5.7%) β-2,1-fructofuranosyl branches. The gel permeation chromatography of the levan fructan EPS showed two main peaks at 4.5 kDa and 8 kDa and a very minor peak at 500 kDa. G. japonicus was identified as a producer of levan fructan. These findings will be useful for future studies aimed at evaluating the impact of levan fructans on sugar crop processing, which have been historically underestimated in industry.

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Yamamoto, Takanobu, Sawako Yada, Yuji Matsuda, Hirofumi Otani, Shunji Yoshikawa, Taro Sasaoka, Yu Hatano, et al. "A Novel Rotablator Technique (Low-Speed following High-Speed Rotational Atherectomy) Can Achieve Larger Lumen Gain: Evaluation Using Optimal Frequency Domain Imaging." Journal of Interventional Cardiology 2019 (May 20, 2019): 1–7. http://dx.doi.org/10.1155/2019/9282876.

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Background. While the evaluation of burr speed was discussed regarding platelet aggregation, the association between platform speed and acute lumen gain of rotational atherectomy remains unknown. Methods. Through the evaluation of the potential of low-speed rotational atherectomy (LSRA) in in-vitro experiments, minimum lumen diameter (MLD) and minimum lumen area (MLA) after conventional high-speed rotational atherectomy (HSRA group) and those after LSRA following HSRA (LSRA+HSRA group) treated by 1.5 mm burrs were measured by optical frequency domain imaging (OFDI) in 30 consecutive human lesions. Results. The in-vitro experiments demonstrated that MLD and MLA after LSRA+HSRA were significantly larger (MLD: LSRA+HSRA=1.50 ±0.05 mm, HSRA= 1.43 ±0.05 mm, p=0.015; MLA: LSRA+HSRA= 1.90 ±0.17 mm2, HSRA= 1.71±0.11 mm2, and p= 0.037), requiring more crossing attempts (LSRA= 134 ±20 times, HSRA= 72 ±11 times, and p< 0.001). In human studies, there was no significance in reference vessel diameter and lesion length before the procedure between two groups. MLDs after LSRA+HSRA were significantly larger than those in HSRA (LSRA+HSRA= 1.22 ±0.16 mm, HSRA= 1.07 ±0.14 mm, and p= 0.0078), while MLAs after LSRA+HSRA tended to be larger (LSRA+HSRA= 1.79 ±0.51 mm2, HSRA= 1.55 ±0.47 mm2, and p= 0.19). There was no significance in the occurrence of in-hospital complication, including slow flow or no reflow, major dissection, and procedural myocardial infarction, between LSRA+HSRA and HSRA. Conclusions. LSRA can achieve larger lumen gain compared, whereas HSRA can pass calcified lesions easily. Combination of LSRA and HSRA is a safe and feasible strategy for severely calcified lesions in clinical practice.

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Kim, Hyun-Min, and Zifei Liu. "LSD2 Is an Epigenetic Player in Multiple Types of Cancer and Beyond." Biomolecules 14, no. 5 (May 3, 2024): 553. http://dx.doi.org/10.3390/biom14050553.

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Histone demethylases, enzymes responsible for removing methyl groups from histone proteins, have emerged as critical players in regulating gene expression and chromatin dynamics, thereby influencing various cellular processes. LSD2 and LSD1 have attracted considerable interest among these demethylases because of their associations with cancer. However, while LSD1 has received significant attention, LSD2 has not been recognized to the same extent. In this study, we conduct a comprehensive comparison between LSD2 and LSD1, with a focus on exploring LSD2’s implications. While both share structural similarities, LSD2 possesses unique features as well. Functionally, LSD2 shows diverse roles, particularly in cancer, with tissue-dependent roles. Additionally, LSD2 extends beyond histone demethylation, impacting DNA methylation, cancer cell reprogramming, E3 ubiquitin ligase activity and DNA damage repair pathways. This study underscores the distinct roles of LSD2, providing insights into their contributions to cancer and other cellular processes.

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Marayati, Bahjat F., James F. Tucker, David A. De La Cerda, Tien-Chi Hou, Rong Chen, Tomoyasu Sugiyama, James B. Pease, and Ke Zhang. "The Catalytic-Dependent and -Independent Roles of Lsd1 and Lsd2 Lysine Demethylases in Heterochromatin Formation in Schizosaccharomyces pombe." Cells 9, no. 4 (April 13, 2020): 955. http://dx.doi.org/10.3390/cells9040955.

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In eukaryotes, heterochromatin plays a critical role in organismal development and cell fate acquisition, through regulating gene expression. The evolutionarily conserved lysine-specific demethylases, Lsd1 and Lsd2, remove mono- and dimethylation on histone H3, serving complex roles in gene expression. In the fission yeast Schizosaccharomyces pombe, null mutations of Lsd1 and Lsd2 result in either severe growth defects or inviability, while catalytic inactivation causes minimal defects, indicating that Lsd1 and Lsd2 have essential functions beyond their known demethylase activity. Here, we show that catalytic mutants of Lsd1 or Lsd2 partially assemble functional heterochromatin at centromeres in RNAi-deficient cells, while the C-terminal truncated alleles of Lsd1 or Lsd2 exacerbate heterochromatin formation at all major heterochromatic regions, suggesting that Lsd1 and Lsd2 repress heterochromatic transcripts through mechanisms both dependent on and independent of their catalytic activities. Lsd1 and Lsd2 are also involved in the establishment and maintenance of heterochromatin. At constitutive heterochromatic regions, Lsd1 and Lsd2 regulate one another and cooperate with other histone modifiers, including the class II HDAC Clr3 and the Sirtuin family protein Sir2 for gene silencing, but not with the class I HDAC Clr6. Our findings explore the roles of lysine-specific demethylases in epigenetic gene silencing at heterochromatic regions.

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Xu, Yijie, Chunlan Zeng, Huiqi Wen, Qianqian Shi, Xu Zhao, Qingbin Meng, Xingzhou Li, and Junhai Xiao. "Discovery of AI-2 Quorum Sensing Inhibitors Targeting the LsrK/HPr Protein–Protein Interaction Site by Molecular Dynamics Simulation, Virtual Screening, and Bioassay Evaluation." Pharmaceuticals 16, no. 5 (May 12, 2023): 737. http://dx.doi.org/10.3390/ph16050737.

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Quorum sensing (QS) is a cell-to-cell communication mechanism that regulates bacterial pathogenicity, biofilm formation, and antibiotic sensitivity. Among the identified quorum sensing, AI-2 QS exists in both Gram-negative and Gram-positive bacteria and is responsible for interspecies communication. Recent studies have highlighted the connection between the phosphotransferase system (PTS) and AI-2 QS, with this link being associated with protein-protein interaction (PPI) between HPr and LsrK. Here, we first discovered several AI-2 QSIs targeting the LsrK/HPr PPI site through molecular dynamics (MD) simulation, virtual screening, and bioassay evaluation. Of the 62 compounds purchased, eight compounds demonstrated significant inhibition in LsrK-based assays and AI-2 QS interference assays. Surface plasmon resonance (SPR) analysis confirmed that the hit compound 4171-0375 specifically bound to the LsrK-N protein (HPr binding domain, KD = 2.51 × 10−5 M), and therefore the LsrK/HPr PPI site. The structure-activity relationships (SARs) emphasized the importance of hydrophobic interactions with the hydrophobic pocket and hydrogen bonds or salt bridges with key residues of LsrK for LsrK/HPr PPI inhibitors. These new AI-2 QSIs, especially 4171-0375, exhibited novel structures, significant LsrK inhibition, and were suitable for structural modification to search for more effective AI-2 QSIs.

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Ha, Jung-Hye, Eun-Hee Kim, Hae-Kap Cheong, and Kyoung-Seok Ryu. "Crystal structures of LsrR complexed with p-AI-2 reveal distinct mechanisms." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C580. http://dx.doi.org/10.1107/s2053273314094194.

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Quorum sensing (QS) is a cell-to-cell communication system and responsible for a variety of bacterial phenotypes including virulence and biofilm formation. QS is mediated by small molecules, autoinducers (AIs), including AI-2 that is secreted by both Gram (+/–) microbes. LsrR is a key transcriptional regulator that governs the varied downstream processes by perceiving AI-2 signal, but its activation via autoinducer-binding remains poorly understood [1]. The ligand-free crystals of LsrR and complex crystals of LsrR and C-LsrR with 5 mM R5P were grown with reservoir buffer. Complex crystal of C-LsrR/D5P and C-LsrR/D8P were obtainded by soaking the native crystals in the same crystallization buffer (pH 6.5, 0.1 M bis-tris, 9.1% PEG-3350, 10 mM barium chloride dehydrate, 10 mM R5P) containing 0.15mM D5P and 2.0 mM D8P. These crystals were determined its 3-demensional (3D) structure at 3.2 Å ~ 1.9 Å resolution after SAD phasing. The ligand-binding affinities for LsrR protein were measured using fluorescence spectrophotometer and Isothermal titration calorimetry (ITC) while increasing the ligand concentrations. Detailed regulatory mechanism of LsrR from the crystal structures in complexes with the native signal (phospho-AI-2, D5P) and two quorum quenching antagonists (ribose-5-phosphate, R5P; phosphoisobutyl-AI-2, D8P). The bound D5P and D8P molecules are not the diketone forms but rather hydrated, and the hydrated moiety forms important H-bonds with the carboxylate of D243. The D5P-binding flipped out F124 of the binding pocket, and resulted in the disruption of the dimeric interface-1 by unfolding the α7 segment. However, the same movement of F124 by the D8P'-binding did not cause the unfolding of the α7 segment. Although the LsrR-binding affinity of R5P (Kd, ~1 mM) is much lower than those of D5P and D8P (~2.0 and ~0.5 μM), the α-anomeric R5P molecule fits into the binding pocket without any structural perturbation, and thus stabilizes the LsrR tetramer. The binding of D5P, not D8P and R5P, disrupted the tetrameric structure and thus is able to activate LsrR. The detailed structural and mechanistic insights from this study could be useful for facilitating design of new anti-virulence and anti-biofilm agents based on LsrR.

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Du, Mei Hui, Min Zhao, Lei Lu, Tian Nv Wang, Tai Lun Li, Li Yan Zhao, Jun Bo Pan, Guo Fu Li, and Jun Li. "Isolation and Dye Decolorization of a Bacillus subtilis Strain LS02 Exhibiting Laccase Activity." Advanced Materials Research 183-185 (January 2011): 839–43. http://dx.doi.org/10.4028/www.scientific.net/amr.183-185.839.

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A newly isolated strain LS02 was estimated for its ability in dye decolorization. The LS02 strain was identified as Bacillus subtilis by the combination of physicochemical tests and 16S rDNA sequence analysis. The isolated strain could oxidize the laccase substrate syringaldazine, indicating the existence of laccase activity. B. subtilis LS02 grown well in the pH range of 5.0~9.0, and showed an optimum growth temperature at 37°C. Indigo carmine could be completely decolorized by B. subtilis LS02 after 4 days, whereas Remazol Brilliant Blue R, reactive black 5 and crystal violet were poorly decolorized. The result indicated that the laccase of B. subtilis LS02 may be suitable for the application in textile bleaching of indigo carmine.

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Chiou, Sheng-Yuan, Chih-Kai Chao, and Ya-Wun Yang. "Topography of Low Skin Resistance Points (LSRP) in Rats." American Journal of Chinese Medicine 26, no. 01 (January 1998): 19–27. http://dx.doi.org/10.1142/s0192415x9800004x.

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Based on the electrical properties of the skin, a method empolying the unijunction transistor (UJT) relaxation oscillator for detecting low skin resistance points (LSRP) was developed in this study. By means of this instrumentation, the topography of the LSRP in Wistar rats was developed. All the LSRP in the rats were found to be bilaterally and symmetrically distributed except those points located on the dorsal midline (i.e., governor vessel, GV) and the ventral midline (i.e., conception vessel, CV). The resistances of the LSRP on these two major vessels, including 14 CV points and 17 GV points of six rats were experimentally determined to be in the ranges of 179.4 ± 41.2 KΩ and 152.5 ± 32.2 KΩ respectively. The resistances of the GV points were found in general to be lower than those of the CV points. Most non-LSRP, on the other hard, exhibited resistances of greater than 420 KΩ. It is noted that the resistances of most LSRP increased yet still retained a separate identity within thirty minutes after the death of the animals, but the low resistance properties of some LSRP gradually disappeared thereafter and could not be detected by the relaxation oscillator.

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Shou, Yiyun, Martin Sellbom, and Jin Han. "Evaluating the Construct Validity of the Levenson Self-Report Psychopathy Scale in China." Assessment 24, no. 8 (March 11, 2016): 1008–23. http://dx.doi.org/10.1177/1073191116637421.

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The Levenson Self-Report Psychopathy (LSRP) scale is an efficient measure of psychopathy with promising psychometric properties. However, the cross-cultural utility of the LSRP has not been well documented, and no study has explored measurement invariance of the LSRP across East Asian and North American samples. We translated the LSRP into Chinese (Study 1) and investigated the validity and reliability of the Chinese LSRP using a sample of 226 university students in China (Study 2). Confirmatory factor analyses supported Brinkley, Diamond, Magaletta, and Heigel’s (2008) three-factor model (Egocentricity, Callousness, and Antisocial). Evidence for configural and partial metric (but not scalar) invariance of the factor structure was observed when comparing Chinese and U.S. university samples. However, response thresholds were significantly different between the two samples. The Chinese LSRP scores also demonstrated encouraging convergent and discriminate validity in terms of their associations with external criteria. We discuss the implications for cross-cultural assessment of psychopathy.

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Md Ghazaly, Mariam, Yeo Chin Kiat, Chong Shin Horng, Norhaslinda Hasim, Zulkeflee Abdullah, and Nurdiana Nordin. "TUBULAR LINEAR SWITCHED RELUCTANCE ACTUATOR: DESIGN AND CHARACTERIZATION." Jurnal Teknologi 84, no. 5 (July 26, 2022): 117–29. http://dx.doi.org/10.11113/jurnalteknologi.v84.17902.

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Linear electromagnetic actuator is receiving significant attention due to recent advances in power electronics and modern control methods. This research proposes a three-phase tubular linear switched reluctance actuator (LSRA) for application in the semiconductor fabrication industry. The tubular LSRA has a robust construction, low manufacturing and maintenance cost, good fault tolerance capability, and high reliability in a harsh environment, making it an attractive alternative to a permanent magnet linear actuator. However, the tubular LSRA has a long mover, which increases the possibility of the mover deforming during fabrication. So, a new mover design is proposed to overcome the problem. The proposed mover design allows the traveling distance of the actuator to be modified by adding or removing the rings without changing the shaft. The tubular LSRA prototype is fabricated according to the optimized design. To drive the tubular LSRA, a appropriate switching algorithm method are used to provide the correct switching signal. This method is straightforward, while no extensive knowledge of power electronic converter is required. The developed tubular LSRA can generate a maximum static force of 0.65N. Through the open-loop reciprocating motion, the dynamic responses of the tubular LSRA can achieve a maximum velocity of 210mm/s and maximum acceleration of 8m/s2, which are in the performance range for precision mechanism.

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Iannizzi, Claire, Elie A. Akl, Lara A. Kahale, Elena Dorando, Abina Mosunmola Aminat, James M. Barker, Joanne E. McKenzie, Neal R. Haddaway, Vanessa Piechotta, and Nicole Skoetz. "Methods and guidance on conducting, reporting, publishing and appraising living systematic reviews: a scoping review protocol." F1000Research 10 (August 13, 2021): 802. http://dx.doi.org/10.12688/f1000research.55108.1.

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Background: The living systematic review (LSR) approach is based on an ongoing surveillance of the literature and continual updating. A few guidance documents address the conduct, reporting, publishing and appraisal of systematic reviews (SRs), but the methodology described is either not up-to date or not suitable for LSRs and misses additional LSR-specific considerations. The objective of this scoping review is to systematically collate methodological literature and guidance on how to conduct, report, publish and appraise the quality of LSRs. The scoping review will allow the mapping of the existing evidence on the topic to support LSRs authors seeking guidance and identify related gaps. Methods: To achieve our objectives, we will conduct a scoping review to survey and evaluate existing evidence, using the standard scoping review methodology. We will search MEDLINE, EMBASE, and Cochrane using the OVID interface. The search strategy was developed by a researcher experienced in developing literature search strategies with the help of an information specialist. As for searching grey literature, we will seek existing guidelines and handbooks on LSRs from organizations that conduct evidence syntheses using the Lens.org website. Two review authors will extract and catalogue the study data on LSR methodological aspects into a standardized and pilot-tested data extraction form. The main categories will reflect proposed methods for (i) conducting LSRs, (ii) reporting of LSRs, (iii) publishing and (iv) appraising the quality of LSRs. Data synthesis and conclusion: By collecting these data from methodological surveys and papers, as well as existing guidance documents and handbooks on LSRs, we might identify specific issues and components lacking within current LSR methodology. Thus, the systematically obtained findings of the scoping review could be used as basis for the revision of existing methods tools on LSR, for instance a PRISMA statement extension for LSRs.

Journal articles on the topic 'Lsr2'

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