scholarly journals Identification, Recombinant Expression, and Characterization of LGH2, a Novel Antimicrobial Peptide of Lactobacillus casei HZ1

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2246 ◽  
Author(s):  
Junfang He ◽  
Xuegang Luo ◽  
Duxin Jin ◽  
Yunyang Wang ◽  
Tongcun Zhang
Keyword(s):  
Amino Acid ◽  
Pathogenic Bacteria ◽  
Recombinant Expression ◽  
Expression System ◽  
Fermented Milk ◽  
Random Coil ◽  
Amino Acid Residues ◽  
Inhibitory Peptide ◽  
Antibiotic Resistant ◽  
E Coli

L. casei HZ1 was identified from Chinese traditional fermented milk, and angiotensin converting enzyme inhibitory peptide was separated from its culture in our previous work. Here, LGH2 was a novel AMP, identified from the genome of L. casei HZ1. Altogether, roughly 52.76% of LGH2 was α -helical, with the remainder in β -strand and random coil in 50% TFE solution tested by CD. The peptide was also an amphipathic and cationic molecule, which was composed of 20 amino acid residues. The similarity of the amino acid sequence between LGH2 and Temporin-RN3 was highest. Then, the peptide successfully expressed in E. coli Rossetta (DE3) pLysS using the SUMO fusion expression system and purified by chromatography technologies. The molecular weight of the peptide was 2448 Da determined by MALDI-TOF MS. Antimicrobial tests showed that the peptide has strong activities against G+ bacteria, special for S. aureus (MIC = 4 μM). The toxicity assay showed that the peptide exhibits a low hemolytic activity against sheep red blood cells. The antimicrobial mechanisms of LGH2 against pathogens were further investigated by dye leakage, CLSM, SEM, and FCM assays. We found that LGH2 can bind to the cell membrane, and destroy its integrity. These significant results indicate that LGH2 has great potential to treat the infections caused by pathogenic bacteria such as S. aureus, and it provides a new template to improve antimicrobial peptides targeting antibiotic-resistant pathogenic bacteria.

Kynurenine aminotransferase and glutamine transaminase K of Escherichia coli: identity with aspartate aminotransferase

2001 ◽  
Vol 360 (3) ◽  
pp. 617-623 ◽  
Author(s):  
Qian HAN ◽  
Jianmin FANG ◽  
Jianyong LI
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Aspartate Aminotransferase ◽  
Expression System ◽  
Xanthurenic Acid ◽  
Amino Acid Residues ◽  
Terminal Amino Acid ◽  
Kynurenine Aminotransferase ◽  
E Coli ◽  
Terminal Amino

The present study describes the isolation of a protein from Escherichia coli possessing kynurenine aminotransferase (KAT) activity and its identification as aspartate aminotransferase (AspAT). KAT catalyses the transamination of kynurenine and 3-hydroxykynurenine to kynurenic acid and xanthurenic acid respectively, and the enzyme activity can be easily detected in E. coli cells. Separation of the E. coli protein possessing KAT activity through various chromatographic steps led to the isolation of the enzyme. N-terminal sequencing of the purified protein determined its first 10 N-terminal amino acid residues, which were identical with those of the E. coli AspAT. Recombinant AspAT (R-AspAT), homologously expressed in an E. coli/pET22b expression system, was capable of catalysing the transamination of both l-kynurenine (Km = 3mM; Vmax = 7.9μmol·min−1·mg−1) and 3-hydroxy-dl-kynurenine (Km = 3.7mM; Vmax = 1.25μmol·min−1·mg−1) in the presence of pyruvate as an amino acceptor, and exhibited its maximum activity at temperatures between 50–60°C and at a pH of approx. 7.0. Like mammalian KATs, R-AspAT also displayed high glutamine transaminase K activity when l-phenylalanine was used as an amino donor (Km = 8mM; Vmax = 20.6μmol·min−1·mg−1). The exact match of the first ten N-terminal amino acid residues of the KAT-active protein with that of AspAT, in conjunction with the high KAT activity of R-AspAT, provides convincing evidence that the identity of the E. coli protein is AspAT.

Expression and partial purification of human pro-opiomelanocortin in Escherichia coli

1989 ◽  
Vol 3 (2) ◽  
pp. 105-112 ◽  
Author(s):  
T. S. Grewal ◽  
P. J. Lowry ◽  
D. Savva
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Fusion Protein ◽  
Western Blot ◽  
Blot Analysis ◽  
Expression Vectors ◽  
Partial Purification ◽  
Amino Acid Residues ◽  
E Coli ◽  
Dna Fragment

ABSTRACT A large portion of the human pro-opiomelanocortin (POMC) peptide corresponding to amino acid residues 59–241 has been cloned and expressed in Escherichia coli. A 1·0 kb DNA fragment encoding this peptide was cloned into the expression vectors pUC8 and pUR291. Plasmid pJMBG51 (a pUC8 recombinant) was found to direct the expression of a 24 kDa peptide. The recombinant pUR291 (pJMBG52) was shown to produce a β-galactosidase fusion protein of 140 kDa. Western blot analysis showed that both the 24 kDa and 140 kDa peptides are recognized by antibodies raised against POMC-derived peptides. The β-galactosidase fusion protein has been partially purified from crude E. coli cell lysates using affinity chromatography on p-aminobenzyl-1-thio-β-d-galactopyranoside agarose.

scholarly journals Mechanisms of Resistance in Multiple-Antibiotic-Resistant Escherichia coli Strains of Human, Animal, and Food Origins

2004 ◽  
Vol 48 (10) ◽  
pp. 3996-4001 ◽  
Author(s):  
Yolanda Sáenz ◽  
Laura Briñas ◽  
Elena Domínguez ◽  
Joaquim Ruiz ◽  
Myriam Zarazaga ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Amino Acid ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Mechanisms Of Resistance ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Class 1 ◽  
Human Animal

ABSTRACT Seventeen multiple-antibiotic-resistant nonpathogenic Escherichia coli strains of human, animal, and food origins showed a wide variety of antibiotic resistance genes, many of them carried by class 1 and class 2 integrons. Amino acid changes in MarR and mutations in marO were identified for 15 and 14 E. coli strains, respectively.

scholarly journals Recombinant expression in E. coli of human FGFR2 with its transmembrane and extracellular domains

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3512 ◽  
Author(s):  
Adam Bajinting ◽  
Ho Leung Ng
Keyword(s):  
Tyrosine Kinases ◽  
Recombinant Expression ◽  
Expression System ◽  
Transmembrane Helix ◽  
Size Exclusion ◽  
Complex Signal ◽  
Tyrosine Kinase Domain ◽  
Fibroblast Growth ◽  
Fibroblast Growth Factor Receptors ◽  
E Coli

Fibroblast growth factor receptors (FGFRs) are a family of receptor tyrosine kinases containing three domains: an extracellular receptor domain, a single transmembrane helix, and an intracellular tyrosine kinase domain. FGFRs are activated by fibroblast growth factors (FGFs) as part of complex signal transduction cascades regulating angiogenesis, skeletal formation, cell differentiation, proliferation, cell survival, and cancer. We have developed the first recombinant expression system in E. coli to produce a construct of human FGFR2 containing its transmembrane and extracellular receptor domains. We demonstrate that the expressed construct is functional in binding heparin and dimerizing. Size exclusion chromatography demonstrates that the purified FGFR2 does not form a complex with FGF1 or adopts an inactive dimer conformation. Progress towards the successful recombinant production of intact FGFRs will facilitate further biochemical experiments and structure determination that will provide insight into how extracellular FGF binding activates intracellular kinase activity.

Prevalence of antibiotic-resistant Escherichia coli isolated from urban and agricultural streams in Canterbury, New Zealand

2019 ◽  
Vol 366 (8) ◽  
Author(s):  
Sophie Van Hamelsveld ◽  
Muyiwa E Adewale ◽  
Brigitta Kurenbach ◽  
William Godsoe ◽  
Jon S Harding ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
New Zealand ◽  
Pathogenic Bacteria ◽  
Freshwater Ecosystems ◽  
Urban Setting ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Mesophilic Bacteria ◽  
Resistant Strains ◽  
Population Counts

Abstract Baseline studies are needed to identify environmental reservoirs of non-pathogenic but associating microbiota or pathogenic bacteria that are resistant to antibiotics and to inform safe use of freshwater ecosystems in urban and agricultural settings. Mesophilic bacteria and Escherichia coli were quantified and isolated from water and sediments of two rivers, one in an urban and one in an agricultural area near Christchurch, New Zealand. Resistance of E. coli to one or more of nine different antibiotics was determined. Additionally, selected strains were tested for conjugative transfer of resistances. Despite having similar concentrations of mesophilic bacteria and E. coli, the rivers differed in numbers of antibiotic-resistant E. coli isolates. Fully antibiotic-susceptible and -resistant strains coexist in the two freshwater ecosystems. This study was the first phase of antibiotic resistance profiling in an urban setting and an intensifying dairy agroecosystem. Antibiotic-resistant E. coli may pose different ingestion and contact risks than do susceptible E. coli. This difference cannot be seen in population counts alone. This is an important finding for human health assessments of freshwater systems, particularly where recreational uses occur downstream.

scholarly journals Paper-based analytical devices for colorimetric detection of S. aureus and E. coli and their antibiotic resistant strains in milk

The Analyst ◽  
2020 ◽  
Vol 145 (22) ◽  
pp. 7320-7329
Author(s):  
Muhammad Asif ◽  
Fazli Rabbi Awan ◽  
Qaiser Mahmood Khan ◽  
Bongkot Ngamsom ◽  
Nicole Pamme
Keyword(s):  
Pathogenic Bacteria ◽  
Colorimetric Detection ◽  
Antibiotic Resistant ◽  
Beta Lactamases ◽  
E Coli ◽  
Milk Samples ◽  
Extended Spectrum Beta Lactamases ◽  
Paper Microfluidic ◽  
Resistant Strains ◽  
Appropriate Prescription

We investigate paper microfluidic devices for detection of pathogenic bacteria and their sensitivity towards β-lactamase and Extended Spectrum Beta Lactamases (ESBLs) in milk samples to enable appropriate prescription of antibiotics for mastitis.

scholarly journals The Antibacterial Potential of Honeydew Honey Produced by Stingless Bee (Heterotrigona itama) against Antibiotic Resistant Bacteria

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 871
Author(s):  
Wen-Jie Ng ◽  
Nam-Weng Sit ◽  
Peter Aun-Chuan Ooi ◽  
Kah-Yaw Ee ◽  
Tuck-Meng Lim
Keyword(s):  
Honey Bee ◽  
Pathogenic Bacteria ◽  
Apis Cerana ◽  
Stingless Bee ◽  
Morphological Alteration ◽  
Resistant Bacteria ◽  
Antibacterial Effects ◽  
Electron Microscopic ◽  
Antibiotic Resistant ◽  
E Coli

Scientific studies about the antibacterial effects of honeydew honey produced by the stingless bee are very limited. In this study, the antibacterial activities of 46 blossom and honeydew honeys produced by both honey bees and stingless bees were evaluated and compared. All bacterial isolates showed varying degrees of susceptibility to blossom and honeydew honeys produced by the honey bee (Apis cerana) and stingless bee (Heterotrigona itama and Geniotrigona thoracica) in agar-well diffusion. All stingless bee honeys managed to inhibit all the isolates but only four out of 23 honey bee honeys achieved that. In comparison with Staphylococcus aureus, Escherichia coli was found to be more susceptible to the antibacterial effects of honey. Bactericidal effects of stingless bee honeys on E. coli were determined with the measurement of endotoxins released due to cell lysis. Based on the outcomes, the greatest antibacterial effects were observed in honeydew honey produced by H. itama. Scanning electron microscopic images revealed the morphological alteration and destruction of E. coli due to the action of this honey. The combination of this honey with antibiotics showed synergistic inhibitory effects on E. coli clinical isolates. This study revealed that honeydew honey produced by H. itama stingless bee has promising antibacterial activity against pathogenic bacteria, including antibiotic resistant strains.

Identification of Important Amino Acid Residues of the Na + -Ca 2+ Exchanger Inhibitory Peptide, XIP

1997 ◽  
Vol 156 (2) ◽  
pp. 149-156 ◽  
Author(s):  
Z. He ◽  
N. Petesch ◽  
K.-P. Voges ◽  
W. Röben ◽  
K.D. Philipson
Keyword(s):  
Amino Acid ◽  
Amino Acid Residues ◽  
Inhibitory Peptide ◽  
Important Amino Acid

scholarly journals Synthesis of arborane triterpenols by a bacterial oxidosqualene cyclase

2016 ◽  
Vol 114 (2) ◽  
pp. 245-250 ◽  
Author(s):  
Amy B. Banta ◽  
Jeremy H. Wei ◽  
Clare C. C. Gill ◽  
José-Luis Giner ◽  
Paula V. Welander
Keyword(s):  
Amino Acid ◽  
Broad Class ◽  
Heterotrophic Bacterium ◽  
Expression System ◽  
Amino Acid Residues ◽  
Biologically Relevant ◽  
Oxidosqualene Cyclase ◽  
Membrane Structure And Function ◽  
Terrestrial Input ◽  
And Function

Cyclic triterpenoids are a broad class of polycyclic lipids produced by bacteria and eukaryotes. They are biologically relevant for their roles in cellular physiology, including membrane structure and function, and biochemically relevant for their exquisite enzymatic cyclization mechanism. Cyclic triterpenoids are also geobiologically significant as they are readily preserved in sediments and are used as biomarkers for ancient life throughout Earth's history. Isoarborinol is one such triterpenoid whose only known biological sources are certain angiosperms and whose diagenetic derivatives (arboranes) are often used as indicators of terrestrial input into aquatic environments. However, the occurrence of arborane biomarkers in Permian and Triassic sediments, which predates the accepted origin of angiosperms, suggests that microbial sources of these lipids may also exist. In this study, we identify two isoarborinol-like lipids, eudoraenol and adriaticol, produced by the aerobic marine heterotrophic bacterium Eudoraea adriatica. Phylogenetic analysis demonstrates that the E. adriatica eudoraenol synthase is an oxidosqualene cyclase homologous to bacterial lanosterol synthases and distinct from plant triterpenoid synthases. Using an Escherichia coli heterologous sterol expression system, we demonstrate that substitution of four amino acid residues in a bacterial lanosterol synthase enabled synthesis of pentacyclic arborinols in addition to tetracyclic sterols. This variant provides valuable mechanistic insight into triterpenoid synthesis and reveals diagnostic amino acid residues to differentiate between sterol and arborinol synthases in genomic and metagenomic datasets. Our data suggest that there may be additional bacterial arborinol producers in marine and freshwater environments that could expand our understanding of these geologically informative lipids.

scholarly journals E. coli GyrA Tower Domain Interacts with QnrB1 Loop B and Plays an Important Role in QnrB1 Protection from Quinolone Inhibition

2021 ◽  
Author(s):  
Chunhui Chen ◽  
Yin Wang ◽  
Hidemasa Nakaminami ◽  
Eu Suk Kim ◽  
George A. Jacoby ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Amino Acid ◽  
Dna Gyrase ◽  
Amino Acid Residues ◽  
Site Specific ◽  
E Coli ◽  
Small Deletion ◽  
Interaction Sites ◽  
Repeat Proteins

The Qnr pentapeptide repeat proteins interact with DNA gyrase and protect it from quinolone inhibition. The two external loops, particularly the larger loop B, of Qnr proteins are essential for quinolone protection of DNA gyrase. The specific QnrB1 interaction sites on DNA gyrase are not known. In this study, we investigated the interaction between GyrA and QnrB1 using site-specific photo crosslinking of QnrB1 loop B combined with mass spectrometry. We found that amino acid residues 286-298 on the Tower domain of GyrA interact with QnrB1 and play a key role in QnrB1 protection of gyrase from quinolone inhibition. Alanine replacement of arginine at residue 293 and a small deletion of amino acids 286-289 of GyrA resulted in a decrease in the QnrB1-mediated increase in quinolone MICs and also abolished the QnrB1 protection of purified DNA gyrase from ciprofloxacin inhibition.

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