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https://www.readbyqxmd.com/read/28535062/supramolecular-hydrogel-formation-in-a-series-of-self-assembling-lipopeptides-with-varying-lipid-chain-length
#1
Valeria Castelletto, Amanpreet Kaur, Radoslaw M Kowalczyk, Ian W Hamley, Mehedi Reza, Janne Ruokolainen
The self-assembly in aqueous solution of three lipopeptides comprising a bioactive motif conjugated at the N terminus to dodecyl, tetradecyl or hexadecyl lipid chains has been examined. The bioactive motif is the peptide block YEALRVANEVTLN; a C-terminal fragment of the lumican proteoglycan. This study was motivated by our previous studies on the hexadecyl homologue C16-YEALRVANEVTLN which showed aggregation into β-sheet structures above a critical aggregation concentration (cac), but most remarkably we found that these aggregates were stable to dilution below the cac...
May 23, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28535042/dudawalamides-a-d-antiparasitic-cyclic-depsipeptides-from-the-marine-cyanobacterium-moorea-producens
#2
Jehad Almaliti, Karla L Malloy, Evgenia Glukhov, Carmenza Spadafora, Marcelino Gutiérrez, William H Gerwick
A family of 2,2-dimethyl-3-hydroxy-7-octynoic acid (Dhoya)-containing cyclic depsipeptides, named dudawalamides A-D (1-4), was isolated from a Papua New Guinean field collection of the cyanobacterium Moorea producens using bioassay-guided and spectroscopic approaches. The planar structures of dudawalamides A-D were determined by a combination of 1D and 2D NMR experiments and MS analysis, whereas the absolute configurations were determined by X-ray crystallography, modified Marfey's analysis, chiral-phase GCMS, and chiral-phase HPLC...
May 23, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28533236/antibacterial-and-antibiofilm-activities-of-a-novel-synthetic-cyclic-lipopeptide-against-cariogenic-streptococcus-mutans-ua159
#3
Kyung R Min, Adriana Galvis, Brandon Williams, Ramanjaneyulu Rayala, Predrag Cudic, Dragana Ajdic
Despite continuous efforts to control cariogenic dental biofilms, very few effective antimicrobial treatments exist. In this study, we characterized the activity of a novel synthetic cyclic lipopeptide 4 (CLP-4), derived from fusaricidin, against the cariogenic pathogen Streptococcus mutans UA159. We determined CLP-4's minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), spontaneous resistance frequency, and we performed time-kill assays. Additionally, we assessed CLP-4's potential to inhibit biofilm formation (MBIC) and eradicate pre-formed biofilms (MBEC)...
May 22, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28528498/lipopeptides-produced-by-bacillus-subtilis-as-new-biocontrol-products-against-fusariosis-in-ornamental-plants
#4
Gabriela Mihalache, Tiberius Balaes, Irina Gostin, Marius Stefan, François Coutte, François Krier
In this study, we have investigated the effects of three lipopeptides (fengycin, surfactin and mycosubtilin) produced by different strains of Bacillus subtilis against the phytopathogenic fungi Fusarium oxysporum f. sp. iridacearum, which affects the ornamental bulb plant populations of Iris sp. The antifungal effects were tested using minimum inhibitory concentration assay, determination of mycelium growth and spore germination inhibition rates. Also, in vivo tests on infected rhizomes and scanning electron microscopy were employed...
May 20, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28527355/antimycotic-activity-of-fengycin-c-biosurfactant-and-its-interaction-with-phosphatidylcholine-model-membranes
#5
Lina María González-Jaramillo, Francisco José Aranda, José Antonio Teruel, Valeska Villegas-Escobar, Antonio Ortiz
Lipopeptide biosurfactants constitute one of the most promising groups of compounds for the treatment and prevention of fungal diseases in plants. Bacillus subtilis strain EA-CB0015 produces iturin A, fengycin C and surfactin and it has been proven useful for the treatment of black Sigatoka disease in banana plants, an important pathology caused by the fungus Mycosphaerella fijiensis (Morelet). We have found that B. subtilis EA-CB0015 cell free supernatants and purified fractions inhibit M. fijiensis cellular growth...
May 10, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28526864/a-broad-spectrum-bactericidal-lipopeptide-with-anti-biofilm-properties
#6
Ohad Meir, Fadia Zaknoon, Uri Cogan, Amram Mor
Previous studies of the oligoacyllysyl (OAK) series acyl-lysyl-lysyl-aminoacyl-lysine-amide, suggested their utility towards generating robust linear lipopeptide-like alternatives to antibiotics, although to date, none exhibited potent broad-spectrum bactericidal activity. To follow up on this premise, we produced a new analog (C14KKc12K) and investigated its properties in various media. Mechanistic studies suggest that C14KKc12K uses a non-specific membrane-disruptive mode of action for rapidly reducing viability of Gram-negative bacteria (GNB) similarly to polymyxin B (PMB), a cyclic lipopeptide used as last resort antibiotic...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28522726/draft-genome-sequences-of-bacillus-cereus-e41-and-bacillus-anthracis-f34-isolated-from-algerian-salt-lakes
#7
Mohamed Seghir Daas, Albert Remus R Rosana, Jeella Z Acedo, Farida Nateche, Salima Kebbouche-Gana, John C Vederas, Rebecca J Case
Two strains of Bacillus, B. cereus E41 and B. anthracis F34, were isolated from a salt lake in Aïn M'lila-Oum El Bouaghi, eastern Algeria, and Ain Baida-Ouargla, southern Algeria, respectively. Their genomes display genes for the production of several bioactive secondary metabolites, including polyhydroxyalkanoate, iron siderophores, lipopeptides, and bacteriocins.
May 18, 2017: Genome Announcements
https://www.readbyqxmd.com/read/28509357/characterization-of-microbial-mixtures-by-mass-spectrometry
#8
REVIEW
Todd R Sandrin, Plamen A Demirev
MS applications in microbiology have increased significantly in the past 10 years, due in part to the proliferation of regulator-approved commercial MALDI MS platforms for rapid identification of clinical infections. In parallel, with the expansion of MS technologies in the "omics" fields, novel MS-based research efforts to characterize organismal as well as environmental microbiomes have emerged. Successful characterization of microorganisms found in complex mixtures of other organisms remains a major challenge for researchers and clinicians alike...
May 16, 2017: Mass Spectrometry Reviews
https://www.readbyqxmd.com/read/28499818/biosurfactant-biopolymer-driven-microbial-enhanced-oil-recovery-meor-and-its-optimization-by-an-ann-ga-hybrid-technique
#9
Gunaseelan Dhanarajan, Vivek Rangarajan, Chandrakanth Bandi, Abhivyakti Dixit, Susmita Das, Kranthikiran Ale, Ramkrishna Sen
A lipopeptide biosurfactant produced by marine Bacillus megaterium and a biopolymer produced by thermophilic Bacillus licheniformis were tested for their application potential in the enhanced oil recovery. The crude biosurfactant obtained after acid precipitation effectively reduced the surface tension of deionized water from 70.5 to 28.25mN/m and the interfacial tension between lube oil and water from 18.6 to 1.5mN/m at a concentration of 250mgL(-1). The biosurfactant exhibited a maximum emulsification activity (E24) of 81...
May 10, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28492366/digitizing-mass-spectrometry-data-to-explore-the-chemical-diversity-and-distribution-of-marine-cyanobacteria-and-algae
#10
Tal Luzzatto-Knaan, Neha Garg, Mingxun Wang, Evgenia Glukhov, Yao Peng, Gail Ackermann, Amnon Amir, Brendan M Duggan, Sergey Ryazanov, Lena Gerwick, Rob Knight, Theodore Alexandrov, Nuno Bandeira, William H Gerwick, Pieter C Dorrestein
Natural product screening programs have uncovered molecules from diverse natural sources with various biological activities and unique structures. However, much is yet underexplored and additional information is hidden in these exceptional collections. We applied untargeted mass spectrometry approaches to capture the chemical space and dispersal patterns of metabolites from an in-house library of marine cyanobacterial and algal collections. Remarkably, 86% of the metabolomics signals detected were not found in other available datasets of similar nature, supporting the hypothesis that marine cyanobacteria and algae possess distinctive metabolomes...
May 11, 2017: ELife
https://www.readbyqxmd.com/read/28492230/targeting-the-deubiquitinase-stambp-inhibits-nalp7-inflammasome-activity
#11
Joseph S Bednash, Nathaniel Weathington, James Londino, Mauricio Rojas, Dexter L Gulick, Robert Fort, SeungHye Han, Alison C McKelvey, Bill B Chen, Rama K Mallampalli
Inflammasomes regulate innate immune responses by facilitating maturation of inflammatory cytokines, interleukin (IL)-1β and IL-18. NACHT, LRR and PYD domains-containing protein 7 (NALP7) is one inflammasome constituent, but little is known about its cellular handling. Here we show a mechanism for NALP7 protein stabilization and activation of the inflammasome by Toll-like receptor (TLR) agonism with bacterial lipopolysaccharide (LPS) and the synthetic acylated lipopeptide Pam3CSK4. NALP7 is constitutively ubiquitinated and recruited to the endolysosome for degradation...
May 11, 2017: Nature Communications
https://www.readbyqxmd.com/read/28489343/rearranged-biosynthetic-gene-cluster-and-synthesis-of-hassallidin-e-in-planktothrix-serta-pcc-8927
#12
Claire Pancrace, Jouni Jokela, Nathalie Sassoon, Christelle Ganneau, Marie Desnos-Ollivier, Matti Wahlsten, Anu Humisto, Alexandra Calteau, Sylvie Bay, David P Fewer, Kaarina Sivonen, Muriel Gugger
Cyanobacteria produce a wide range of natural products with antifungal bioactivity. The cyclic glycosylated lipopeptides of the hassallidin family have potent antifungal activity and display a great degree of chemical diversity. Here we report the discovery of a hassallidin biosynthetic gene cluster from the filamentous cyanobacterium Planktothrix serta PCC 8927. The hassallidin gene cluster showed heavy rearrangement and marks of genomic plasticity. Nucleotide bias, differences in GC content and phylogenetic incongruence suggested the acquisition of the hassallidin biosynthetic gene cluster in Planktothrix serta PCC 8927 by horizontal gene transfer...
May 10, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28480267/primary-outcomes-from-a-phase-3-randomized-double-blind-active-controlled-trial-of-surotomycin-in-subjects-with-clostridium-difficile-infection
#13
Vicente Boix, Richard N Fedorak, Kathleen M Mullane, Yves Pesant, Uschi Stoutenburgh, Mandy Jin, Adedayo Adedoyin, Laurent Chesnel, Dalya Guris, Kajal B Larson, Yoshihiko Murata
BACKGROUND: Although the incidence of Clostridium difficile infection (CDI) is increasing, available CDI treatment options are limited in terms of sustained response after treatment. This phase 3 trial assessed the efficacy and safety of surotomycin, a novel bactericidal cyclic lipopeptide, versus oral vancomycin in subjects with CDI. METHODS: In this randomized, double-blind, active-controlled, multicenter, international trial, subjects with CDI confirmed by a positive toxin result were randomized to receive surotomycin (250 mg twice daily) or vancomycin (125 mg 4 times daily) orally for 10 days...
2017: Open Forum Infectious Diseases
https://www.readbyqxmd.com/read/28477175/plipastatin-and-surfactin-coproduction-by-bacillus-subtilis-pb2-l-and-their-effects-on-microorganisms
#14
Ling Gao, Jinzhi Han, Hongxia Liu, Xiaoxu Qu, Zhaoxin Lu, Xiaomei Bie
To convert the lipopeptide non-producer strain Bacillus subtilis pB2 into a plipastatin and surfactin coproducer, a gene expression cassette composed of a constitutive promoter (P43), functional gene sfp, and pleiotropic regulatory gene degQ was integrated into the chromosomal amyE locus of strain B. subtilis pB2 by homologous recombination, which generated a plipastatin and surfactin co-producer. Thirteen plipastatins and fifteen surfactins were identified in lipopeptide extracts using analytical techniques, and their effects on microorganisms were described by microscopic, cytoskeleton analysis and flow-cytometry, respectively...
May 5, 2017: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/28463513/characterization-of-the-polymyxin-d-synthetase-biosynthetic-cluster-and-product-profile-of-paenibacillus-polymyxa-atcc-10401
#15
Charles A Galea, Meiling Han, Yan Zhu, Kade Roberts, Jiping Wang, Philip E Thompson, Jian L, Tony Velkov
The increasing prevalence of polymyxin-resistant bacteria has stimulated the search for improved polymyxin lipopeptides. Here we describe the sequence and product profile for polymyxin D nonribosomal peptide synthetase from Paenibacillus polymyxa ATCC 10401. The polymyxin D synthase gene cluster comprised five genes that encoded ABC transporters (pmxC and pmxD) and enzymes responsible for the biosynthesis of polymyxin D (pmxA, pmxB, and pmxE). Unlike polymyxins B and E, polymyxin D contains d-Ser at position 3 as opposed to l-α,γ-diaminobutyric acid and has an l-Thr at position 7 rather than l-Leu...
May 2, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28459579/modulation-of-activity-of-ultrashort-lipopeptides-toward-negatively-charged-model-lipid-films
#16
Joanna M Wenda, Joanna Juhaniewicz, Dagmara Tymecka, Dorota Konarzewska, Sławomir Sęk
Because of the increasing resistance of pathogens to commonly used antibiotics, there is an urgent need to find alternative antimicrobial compounds with different mechanisms of action. Among them, lipopeptides are recognized as promising candidates. In this work, the Langmuir technique and atomic force microscopy were employed to investigate the interactions of two novel lipopeptides with negatively charged phospholipid membranes, which served as a simplified model of inner membrane of Gram-negative bacteria...
May 5, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28455613/polymyxin-b-inhibits-the-chaperone-activity-of-plasmodium-falciparum-hsp70
#17
Tawanda Zininga, Ofentse J Pooe, Pertunia B Makhado, Lebogang Ramatsui, Earl Prinsloo, Ikechukwu Achilonu, Heinrich Dirr, Addmore Shonhai
Heat shock protein 70 (Hsp70) is a molecular chaperone that plays an important role in cellular proteostasis. Hsp70s are also implicated in the survival and pathogenicity of malaria parasites. The main agent of malaria, Plasmodium falciparum, expresses six Hsp70s. Of these, two (PfHsp70-1 and PfHsp70-z) localize to the parasite cytosol. Previously conducted gene knockout studies suggested that PfHsp70-z is essential, and it has been demonstrated that small-molecule inhibitors targeting PfHsp70-1 cause parasite death...
April 28, 2017: Cell Stress & Chaperones
https://www.readbyqxmd.com/read/28454713/fengycin-produced-by-bacillus-subtilis-9407-plays-a-major-role-in-the-biocontrol-of-apple-ring-rot-disease
#18
Haiyan Fan, Jinjiang Ru, Yuanyuan Zhang, Qi Wang, Yan Li
Apple ring rot, caused by Botryosphaeria dothidea, is a serious apple disease in China. Bacillus subtilis 9407 was isolated from healthy apples and showed strong antifungal activity against B. dothidea. To identify the primary antifungal compound of B. subtilis 9407 and determine its role in controlling apple ring rot, a transposon mutant library was constructed using TnYLB-1, and a mutant completely defective in antifungal activity was obtained. The gene inactivated in the antifungal activity mutant had 98...
June 2017: Microbiological Research
https://www.readbyqxmd.com/read/28437109/structure-of-the-fundamental-lipopeptide-surfactin-at-the-air-water-interface-investigated-by-sum-frequency-generation-spectroscopy
#19
S A Goussous, M T L Casford, A C Murphy, G P C Salmond, F J Leeper, P B Davies
The lipopeptide surfactin produced by certain strains of Bacillus subtilis is a powerful biosurfactant possessing potentially useful antimicrobial properties. In order to better understand its surface behavior, we have used surface sensitive sum frequency generation (SFG) vibrational spectroscopy in the C-H and C═O stretching regions to determine its structure at the air/water interface. Using surfactin with the leucine groups of the peptide ring perdeuterated, we have shown that a majority of the SFG signals arise from the 4 leucine residues...
May 4, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28432441/direct-quantification-of-lipopeptide-biosurfactants-in-biological-samples-via-hplc-and-uplc-ms-requires-sample-modification-with-an-organic-solvent
#20
Piotr Biniarz, Marcin Łukaszewicz
The rapid and accurate quantification of biosurfactants in biological samples is challenging. In contrast to the orcinol method for rhamnolipids, no simple biochemical method is available for the rapid quantification of lipopeptides. Various liquid chromatography (LC) methods are promising tools for relatively fast and exact quantification of lipopeptides. Here, we report strategies for the quantification of the lipopeptides pseudofactin and surfactin in bacterial cultures using different high- (HPLC) and ultra-performance liquid chromatography (UPLC) systems...
April 22, 2017: Applied Microbiology and Biotechnology
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