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Nicholas Harris, David Born, Wenlong Cai, Yaobing Huang, Joelle Martin, Ryan Khalaf, Catherine Drennan, Wenjun Zhang
The electron-rich isonitrile is an important functionality in bioactive natural products, but its biosynthesis has been restricted to the IsnA family of isonitrile synthases. We here provide the first structural and biochemical evidence of an alternative mechanism for isonitrile formation. ScoE, a putative non-heme iron(II)-dependent enzyme from Streptomyces coeruleorubidus, was shown to catalyze the conversion of (R)-3-((carboxymethyl)amino)butanoic acid to (R)-3-isocyanobutanoic acid through an oxidative decarboxylation mechanism...
June 15, 2018: Angewandte Chemie
Huihui Chong, Jing Xue, Yuanmei Zhu, Zhe Cong, Ting Chen, Yan Guo, Qiang Wei, Yusen Zhou, Chuan Qin, Yuxian He
T-20 (enfuvirtide) is the only approved viral fusion inhibitor, which is used for treatment of HIV-1 infection; however, it has relatively low antiviral activity and easily induces drug resistance. We recently reported a T-20-based lipopeptide fusion inhibitor (LP-40) showing improved anti-HIV activity (Ding et al J Virol, 2017). In this study, we designed LP-50 and LP-51 by refining the structure and function of LP-40. Two new lipopeptides showed dramatically enhanced secondary structures and binding stability and were exceptionally potent inhibitors of HIV-1, HIV-2, simian immunodeficiency virus (SIV), and simian-human chimeric virus (SHIV), with mean IC50 values at very low picomolar concentrations...
June 13, 2018: Journal of Virology
Margot Schlusselhuber, Justine Godard, Muriel Sebban, Benoit Bernay, David Garon, Virginie Seguin, Hassan Oulyadi, Nathalie Desmasures
Biosurfactants such as lipopeptides are amphiphilic compounds produced by microorganisms such as bacteria of the genera of Pseudomonas and Bacillus . Some of these molecules proved to have interesting antimicrobial, antiviral, insecticide, and/or tensioactive properties that are potentially useful for the agricultural, chemical, food, and pharmaceutical industries. Raw milk provides a physicochemical environment that is favorable to the multiplication of a broad spectrum of microorganisms. Among them, psychrotrophic bacterial species, especially members of the genus Pseudomonas , are predominant and colonize milk during cold storage and/or processing...
2018: Frontiers in Microbiology
Anne Fünfhaus, Josefine Göbel, Julia Ebeling, Henriette Knispel, Eva Garcia-Gonzalez, Elke Genersch
American Foulbrood is a worldwide distributed, fatal disease of the brood of the Western honey bee (Apis mellifera). The causative agent of this fatal brood disease is the Gram-positive, spore-forming bacterium Paenibacillus larvae, which can be classified into four different genotypes (ERIC I-IV), with ERIC I and II being the ones isolated from contemporary AFB outbreaks. P. larvae is a peritrichously flagellated bacterium and, hence, we hypothesized that P. larvae is capable of coordinated and cooperative multicellular behaviors like swarming motility and biofilm formation...
June 11, 2018: Scientific Reports
Yu-Li Lin, Pei-Yun Cheng, Chiao-Li Chin, Li-Min Huang, Shr-Yu Lin, Bor-Luen Chiang
To prevent viral infection at the site of entry, mucosal vaccines are potent tools for inducing IgA secretion for defense. Because Toll-like receptor (TLR) ligands serve as strong adjuvants, two ligands that mimic the structure of mycoplasmal and bacterial lipopeptides represent interesting vaccine candidates. Pam3CSK4, a synthetic triacylated lipopeptide, interacts with TLR2/1. Because fibroblast-stimulating lipopeptide-1 (FSL-1), a synthetic diacylated lipopeptide, is recognized by TLR2/6, we targeted the potential immuno-inducibility of Pam3CSK4 and FSL-1 as adjuvants of an enterovirus 71 (EV71) mucosal vaccine...
June 8, 2018: Vaccine
Vivek K Bajpai, Shruti Shukla, Sung-Min Kang, Seung Kyu Hwang, Xinjie Song, Yun Suk Huh, Young-Kyu Han
Current trends in the application of nanomaterials are emerging in the nano-biotechnological sector for development of medicines. Cyanobacteria (blue-green algae) are photosynthetic prokaryotes that have applications to human health and numerous biological activities as dietary supplements. Cyanobacteria produce biologically active and chemically diverse compounds such as cyclic peptides, lipopeptides, fatty acid amides, alkaloids, and saccharides. More than 50% of marine cyanobacteria are potentially exploitable for the extraction of bioactive substances, which are effective in killing cancer cells by inducing apoptotic death...
May 23, 2018: Marine Drugs
Ambrin Sarwar, Günter Brader, Erika Corretto, Gajendar Aleti, Muhammad Abaidullah, Angela Sessitsch, Fauzia Yusuf Hafeez
Bacillus spp. produce a broad spectrum of lipopeptide biosurfactants, among which surfactin, iturin and fengycin are widely studied families. The goals of this study were to characterize the biosurfactant activity of Bacillus spp. and to investigate their motility and biofilm formation capabilities. In addition, we extracted lipopeptides from these bacteria to assess their antifungal activities and analyzed these products by mass spectrometry (MS). B. amyloliquefaciens FZB42, Bacillus sp. NH 217 and B. subtilis NH-100 exhibited excellent biosurfactant and surface spreading activities, whereas B...
2018: PloS One
Krista M Armbruster, Timothy C Meredith
Lipoproteins are important constituents of the bacterial cell envelope and potent activators of the mammalian innate immune response. Despite their significance to both cell physiology and immunology, much remains to be discovered about novel lipoprotein forms, how they are synthesized, and the effect of the various forms on host immunity. To enable thorough studies on lipoproteins, this protocol describes a method for bacterial lipoprotein enrichment and preparation of N-terminal tryptic lipopeptides for structural determination by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)...
May 21, 2018: Journal of Visualized Experiments: JoVE
Xiejun Xu, Xingqing Xiao, Yiming Wang, Shouhong Xu, Honglai Liu
Targeted therapy for cancer requires thermosensitive components in drug carriers for controlled drug release against viral cells. The conformational transition characteristic of leucine zipper-structured lipopeptides is utilized in our lab to modulate the phase transition temperature of liposomes, thus achieving temperature-responsive control. In this study, we computationally examined the conformational transition behaviors of leucine zipper-structured lipopeptides that were modified at the N-terminus by distinct functional groups...
May 31, 2018: Physical Chemistry Chemical Physics: PCCP
Yohei Takeda, Masahiro Azuma, Ryoko Hatsugai, Yukari Fujimoto, Masahito Hashimoto, Koichi Fukase, Misako Matsumoto, Tsukasa Seya
The TLR2 agonist, dipalmitoyl lipopeptide (Pam2LP), has been used as an immune adjuvant without much success. Pam2LP is recognised by TLR2/6 receptors in humans and in mice. This study examined the proliferative activity of cytotoxic T lymphocytes (CTL) using mouse Ag-presenting dendritic cells (DCs) and OT-I assay system, where a library of synthetic Pam2LP was utilised from the Staphylococcus aureus database. Ag-specific CTL expansion and IFN-γ levels largely depended on the Pam2LP peptide sequence. The first Aa is cysteine (Cys), which has an active SH residue to bridge fatty acids, and the second and third Aa are hydrophilic or non-polar...
January 1, 2018: Innate Immunity
Mark A T Blaskovich, Miranda E Pitt, Alysha G Elliott, Matthew A Cooper
The octapeptins are a family of cyclic lipopeptides first reported in the 1970s then largely ignored. At the time, their reported antibiotic activity against polymyxin-resistant bacteria was a curiosity. Today the advent of widespread drug resistance in Gram-negative bacteria has prompted their 'rediscovery'. The paucity of new antibiotics in the clinical pipeline is coupled with a global spread of increasing antibiotic resistance, particularly to meropenem and polymyxins B and E (colistin). Areas covered: We review the original discovery of octapeptins, their recent first chemical syntheses, and their mode of action, then discuss their potential as a new class of antibiotics to treat extensively drug resistant (XDR) Gram-negative infections, with direct comparisons to the closely related polymyxins...
May 31, 2018: Expert Review of Anti-infective Therapy
Minh Thu Nguyen, Loulou Peisl, Francesca Barletta Solari, Arif Luqman, Friedrich Götz
S. aureus contains a certain sub-class of lipoproteins, the so-called lipoprotein-like lipoproteins (Lpls) that represent not only TLR2 ligands but are also involved in host cell invasion. Here we addressed the question, which factors contribute to Lpl-mediated invasion into epithelial cells and keratinocytes. For this we compared the invasiveness of USA300 and its Δ lpl deletion mutant under different conditions. In the presence of the matrix proteins IgG, fibrinogen (Fg), fibronectin (Fn), and fetal bovine serum (FBS) the invasion ratio was increased in both strains, and always more in the USA300 than in its Δ lpl mutant...
May 29, 2018: Infection and Immunity
Sun Hee Moon, En Huang
Two paenipeptin analogues at 4 μg/ml potentiated clarithromycin and rifampicin against carbapenem-resistant Acinetobacter baumannii and Klebsiella pneumoniae strains. The combined treatment significantly increased their antibacterial efficacy in a microbiological medium and in human serum in vitro at therapeutically-relevant concentrations. Moreover, these two paenipeptins analogues showed low cytotoxicity against a human kidney cell line. Therefore, the combination therapy with paenipeptins may be an option for the treatment of antibiotic-resistant bacterial infections...
May 29, 2018: Antimicrobial Agents and Chemotherapy
Nivedita B Singh, Juwon Yim, Seyedehameneh Jahanbakhsh, George Sakoulas, Michael J Rybak
OBJECTIVE: Development of antimicrobial resistance during monotherapy of complicated methicillin-resistant Staphylococcus aureus bacteremia is problematic due to cross-resistance between vancomycin (VAN) and daptomycin, the only approved agents for this condition. Our objective was to demonstrate that development of resistance under conditions of suboptimal VAN (200 mg q 12 h) exposure in S. aureus can be attenuated by addition of cefazolin (CFZ). METHODS: Two strains of S...
April 7, 2018: Diagnostic Microbiology and Infectious Disease
Lianshuai Ding, Song Zhang, Wenbin Guo, Xinhua Chen
Bacillus amyloliquefaciens Pc3 was isolated from Antarctic seawater with antifungal activity. In order to investigate the metabolic regulation mechanism in the biosynthesis of lipopeptides in B. amyloliquefaciens Pc3, GC/MS-based metabolomics was used when exogenous indole was added. The intracellular metabolite profiles showed decreased asparagine, aspartic acid, glutamine, glutamic acid, threonine, valine, isoleucine, hexadecanoic acid, and octadecanoic acid in the indole-treated groups, which were involved in the biosynthesis of lipopeptides...
May 28, 2018: Journal of Microbiology and Biotechnology
Hui Cai, Roushu Zhang, Jared Orwenyo, John Giddens, Qiang Yang, Celia C LaBranche, David C Montefiori, Lai-Xi Wang
HIV-1 envelope glycoproteins gp120 and gp41 are presented on the virus surface as a trimer of heterodimer and are the targets of broadly neutralizing antibodies (bNAbs). We describe here the synthesis and preliminary immunological evaluation of a three-component trivalent HIV-1 V3 glycopeptide immunogen aiming to raise glycopeptide epitope-specific antibodies. Click chemistry confers efficient synthesis of the lipopeptide-glycopeptide conjugate that carries three copies of HIV-1 JR-FL gp120 V3 glycopeptide with a high-mannose glycan at the N332 glycosylation site...
May 23, 2018: ACS Central Science
Ramya Ramachandran, Swetha Ramesh, Srinath Ramkumar, Arunaloke Chakrabarti, Utpal Roy
In the pursuit of new antifungal compounds, five coproduced lipopeptide variants (AF1 to AF5 ) from wild-type Bacillus subtilis RLID 12.1 were identified in our previous study. Out of five, AF4 was identified as a novel lead molecule belonging to the bacillomycin family showing less cytotoxicity at its respective minimum inhibitory concentrations (MIC) evaluated against 81 strains of Candida and Cryptococcus species (including clinical isolates); besides this, AF4 purified in the present study exhibited encouraging MIC values against 10 clinical mycelial fungi...
May 25, 2018: Applied Biochemistry and Biotechnology
Joseph E Spraker, Philipp Wiemann, Joshua A Baccile, Nandhitha Venkatesh, Julia Schumacher, Frank C Schroeder, Laura M Sanchez, Nancy P Keller
Small-molecule signaling is one major mode of communication within the polymicrobial consortium of soil and rhizosphere. While microbial secondary metabolite (SM) production and responses of individual species have been studied extensively, little is known about potentially conserved roles of SM signals in multilayered symbiotic or antagonistic relationships. Here, we characterize the SM-mediated interaction between the plant-pathogenic bacterium Ralstonia solanacearum and the two plant-pathogenic fungi Fusarium fujikuroi and Botrytis cinerea We show that cellular differentiation and SM biosynthesis in F...
May 22, 2018: MBio
Seyedehameneh Jahanbakhsh, Nivedita B Singh, Juwon Yim, Warren E Rose, Michael J Rybak
Biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA) infections are challenging due to increasing antibiotic resistance. Synergistic activity of lipopeptides and lipoglycopeptides with β-lactams has been demonstrated for MRSA, but little is known about biofilm-embedded organisms. Our objective was to evaluate two telavancin (TLV) dosage regimens (7.5 mg/kg and 10 mg/kg q 24h)alone and in combination with ceftaroline (CPT) (600 mg q 8 h) or rifampin (RIF) (450 mg q 12h) against two biofilm-producing MRSA (494 and N315)...
May 21, 2018: Antimicrobial Agents and Chemotherapy
Arun Kumar Pradhan, Animesha Rath, Nilotpala Pradhan, Rupenangshu Kumar Hazra, Rati Ranjan Nayak, Sanjit Kanjilal
Bacillus tequilensis strain CH had been previously shown to produce a biosurfactant. In this study, chemical structure of the purified biosurfactant was determined by using high performance liquid chromatography and liquid chromatography-mass spectroscopy as a 10 amino acid cyclic lipopeptide (CL). The cyclic lipopeptide was found to be active against Anopheles culicifacies larvae with a LC50 of 110 µg/ml in 2 days. 1 ppm cadmium (Cd) which had a profound mutagenic effect on the cell division of onion ( Allium cepa ) root tip cell resulting in abnormal metaphase, abnormal anaphase and nuclei elongation was partially reversed in the presence of 0...
June 2018: 3 Biotech
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