Read by QxMD icon Read


Ipsita Chakravarty, Subir Kundu
The increased threat of drug resistance has challenged the existence of several conventional and non-conventional antibiotics in the recent times. Daptomycin is a novel cyclic-lipopeptide antibiotic produced by Streptomyces roseosporus that has progressed as a significant anti-MRSA (methicillin-resistant Staphylococcus aureus) antibiotic. But, the economic practicality of this highly valued secondary metabolite is deterred by its poor production and tedious processing methodology. The present study aims at strategic improvement of Daptomycin production through morphological variations of S...
December 2016: AMB Express
Qi Deng, Wenjing Wang, Lijun Sun, Yaling Wang, Jianmeng Liao, Defeng Xu, Ying Liu, Riying Ye, Ravi Gooneratne
Surfactin and iturin are antimicrobial lipopeptides produced from Bacillus spp. and have significant prospective applications in many fields. Therefore, accurate analysis of these lipopeptides in the fermented product of some Bacillus strains is important. A sensitive method for simultaneous quantitative determination of surfactin and iturin fermented by Bacillus natto NT-6 was developed and validated using liquid chromatography-tandem mass spectrometry. Crude extracts of antimicrobial lipopeptide samples were dissolved in a mixture of acetonitrile/water (7:3, v/v) in 0...
October 20, 2016: Analytical and Bioanalytical Chemistry
Gillian Hertlein, Marlene Seiffert, Sebastian Gensel, Eva Garcia-Gonzalez, Julia Ebeling, Ranko Skobalj, Anja Kuthning, Roderich D Süssmuth, Elke Genersch
The Gram-positive bacterium Paenibacillus larvae (P. larvae) is the causative agent of a deadly honey bee brood disease called American Foulbrood (AFB). AFB is a notifiable epizootic in most countries and, hence, P. larvae is of considerable relevance for veterinarians and apiculturists alike. Over the last decade, much progress has been made in the understanding of the (patho)biology of P. larvae. Recently, several non-ribosomally produced peptides (NRP) and peptide/polyketide (NRP/PK) hybrids produced by P...
2016: PloS One
Francesca Tamarozzi, Joseph D Turner, Nicolas Pionnier, Angela Midgley, Ana F Guimaraes, Kelly L Johnston, Steven W Edwards, Mark J Taylor
The endosymbiotic bacteria, Wolbachia, induce neutrophilic responses to the human helminth pathogen Onchocerca volvulus. The formation of Neutrophil Extracellular Traps (NETs), has been implicated in anti-microbial defence, but has not been identified in human helminth infection. Here, we demonstrate NETs formation in human onchocerciasis. Extracellular NETs and neutrophils were visualised around O. volvulus in nodules excised from untreated patients but not in nodules from patients treated with the anti-Wolbachia drug, doxycycline...
October 18, 2016: Scientific Reports
Raida Zouari, Dorsaf Moalla-Rekik, Zouheir Sahnoun, Tarek Rebai, Semia Ellouze-Chaabouni, Dhouha Ghribi-Aydi
BACKGROUND: Lipopeptide microbial surfactants are endowed with unique surface properties as well as antimicrobial, anti-wrinkle, moisturizing and free radical scavenging activities. They were introduced safely in dermatological products, as long as they present low cytotoxicity against human cells. The present study was undertaken to evaluate the in vitro antioxidant activities and the wound healing potential of Bacillus subtilis SPB1 lipopeptide biosurfactant on excision wounds induced in experimental rats...
October 14, 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Esther A Guzmán, Dedra Harmody, Tara P Pitts, Brunilda Vera-Diaz, Priscilla L Winder, Yichao Yu, Amy E Wright
Pancreatic cancer presents one of the most negative prognosis of all cancers as it has usually metastasized by the time a patient is diagnosed. The American Cancer Society estimates that 93% of patients will die within 5 years of diagnosis, highlighting the need for new drugs to treat this disease. Interleukin 8 (IL-8) mediates the angiogenesis of tumors arising from Ras mutations, which are present in about 90% of pancreatic adenocarcinomas. Overexpression of IL-8 in pancreatic tumors is believed to promote tumor angiogenesis and to activate survival signaling pathways...
October 5, 2016: Anti-cancer Drugs
Chandradhish Ghosh, Mohini Mohan Konai, Paramita Sarkar, Sandip Samaddar, Jayanta Haldar
In the global effort to thwart antimicrobial resistance, lipopeptides are an important class of antimicrobial agents, especially against Gram-negative infections. In an attempt to circumvent their synthetic complexities, we designed simple membrane-active agents involving only one amino acid and two lipid tails. Herein we show that the use of two short lipid tails instead of a single long one significantly increases selective antibacterial activity. This study yielded several selective antibacterial compounds, and investigations into the properties of this compound class were conducted with the most active compound...
October 12, 2016: ChemMedChem
Jian Yang, Azadeh Bahreman, Geert Daudey, Jeroen Bussmann, René C L Olsthoorn, Alexander Kros
Efficient delivery of drugs to living cells is still a major challenge. Currently, most methods rely on the endocytotic pathway resulting in low delivery efficiency due to limited endosomal escape and/or degradation in lysosomes. Here, we report a new method for direct drug delivery into the cytosol of live cells in vitro and invivo utilizing targeted membrane fusion between liposomes and live cells. A pair of complementary coiled-coil lipopeptides was embedded in the lipid bilayer of liposomes and cell membranes respectively, resulting in targeted membrane fusion with concomitant release of liposome encapsulated cargo including fluorescent dyes and the cytotoxic drug doxorubicin...
September 28, 2016: ACS Central Science
Song Jiao, Xu Li, Huimin Yu, Huan Yang, Xue Li, Zhongyao Shen
Surfactin-family lipopeptides are green biosurfactants with substantial industrial potential. The major problem prohibiting surfactin use is the low titer of the wild producer, Bacillus subtilis. Using transcriptomic analysis, four strong promoters, PgroE, Pcdd, PrplK, and PsspE, were identified and cloned from the genome of B. subtilis THY-7, a novel surfactin producer that has been identified from soil with a 0.55 g/L surfactin titer. An optimal promoter, PgroE, was selected to replace the native THY-7 surfactin synthase (SrfA) promoter through single-cross homologous recombination; however, the resulting engineered strain containing the PgroE substitution did not synthesize surfactin...
October 10, 2016: Biotechnology and Bioengineering
Rustam Aminov
The introduction of antibiotics into clinical practice revolutionized the treatment and management of infectious diseases. Before the introduction of antibiotics, these diseases were the leading cause of morbidity and mortality in human populations. This review presents a brief history of discovery of the main antimicrobial classes (arsphenamines, β-lactams, sulphonamides, polypeptides, aminoglycosides, tetracyclines, amphenicols, lipopeptides, macrolides, oxazolidinones, glycopeptides, streptogramins, ansamycins, quinolones, and lincosamides) that have changed the landscape of contemporary medicine...
October 5, 2016: Biochemical Pharmacology
Junhui Zhang, Quanhong Xue, Hui Gao, Hangxian Lai, Ping Wang
BACKGROUND: Lipopeptides are known as promising microbial surfactants and have been successfully used in enhancing oil recovery in extreme environmental conditions. A biosurfactant-producing strain, Bacillus atrophaeus 5-2a, was recently isolated from an oil-contaminated soil in the Ansai oilfield, Northwest China. In this study, we evaluated the crude oil removal efficiency of lipopeptide biosurfactants produced by B. atrophaeus 5-2a and their feasibility for use in microbial enhanced oil recovery...
October 3, 2016: Microbial Cell Factories
Joachim Vater, Stefanie Herfort, Joerg Doellinger, Max Weydmann, Kristin Dietel, Sebastian Faetke, Peter Lasch
Paenibacillus polymyxa are rhizobacteria with a high potential to produce natural compounds of biotechnological and medical interest. Main products of P. polymyxa are fusaricidins, a large family of antifungal lipopeptides with a 15-guanidino-3-hydroxypentadecanoic acid (GHPD) as fatty acid side chain. We use the P. polymyxa strain M-1 as a model organism for the exploration of the biosynthetic potential of these rhizobacteria. Using matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) about 40 new fusaricidins were detected which were fractionated by reversed-phase (rp) HPLC...
October 6, 2016: Journal of Mass Spectrometry: JMS
Emerson R Silva, Gary Cooney, Ian W Hamley, Wendel A Alves, Shannon Lee, Brendan F O'Connor, Mehedi Reza, Janne Ruokolainen, Dermot Walls
We describe in depth the structure of complexes formed between DNA and two classes of arginine-containing peptide amphiphiles, namely, the lipopeptide PRW-C16 (P = proline, R = arginine, W = tryptophan, C16 = C16 : 0 alkyl chain) and the bolaamphiphile RFL4FR (R = arginine, F = phenylalanine, L = leucine). A combination of X-ray and neutron scattering provided unprecedented insights into the local structure of these complexes. Lipopeptide-based complexes self-assembled into layered structures with large-scale fractal features, hosting DNA in the interstices...
October 7, 2016: Soft Matter
Michael C Pirrung, Fa Zhang, Sudhakar Ambadi, Y Gangadhara Rao
Correction for 'Total synthesis of fellutamides, lipopeptide proteasome inhibitors. More sustainable peptide bond formation' by Michael C. Pirrung, et al., Org. Biomol. Chem., 2016, 14, 8367-8375.
September 26, 2016: Organic & Biomolecular Chemistry
Karl Sydow, Heike Nikolenko, Dorothea Lorenz, Rainer H Müller, Margitta Dathe
Lipopeptide-based micelles and liposomes were found to differ in cell recognition and uptake mode into blood brain barrier (BBB) endothelial cells. Here we analyze the role of size and surface charge of micelles and liposomes composed of different lipopeptide sequences with respect to uptake into human brain capillary (HBMEC) and aortic (HAoEC) endothelial cells. Comparable to the dipalmitoylated apolipoprotein E-derived P2A2, lipopeptides of cationic poly-arginine (P2Rn), poly-lysine (P2Kn) and an anionic glutamic-acid sequence (P2En) self assemble into micelles (12-14 nm in diameter) with high surface charge density, and bind to small (SUVs, about 24 nm in diameter) and large (LUV, about 100 nm in diameter) liposomes at variable lipid to peptide ratios...
October 1, 2016: European Journal of Pharmaceutics and Biopharmaceutics
Wen Ma, Dan Zhang, Guoshun Li, Jingjing Liu, Gu He, Peng Zhang, Li Yang, Hongxia Zhu, Ningzhi Xu, Shufang Liang
: Daptomycin (DAP) is a novel lipopeptide antibiotic which exhibits excellent antibacterial activity against most clinically relevant Gram-positive bacteria, but the DAP-targeting protein molecules against host bacterial infection are far from clear. In order to discover bacterial protein response to DAP treatment, an iTRAQ-based quantitative proteomic analysis was applied to identify differential bacterial proteome profiling of Staphylococcus aureus (S. aureus) ATCC 25923 to 0.125μg/ml DAP exposure...
September 29, 2016: Journal of Proteomics
Daniel E Otzen
Biosurfactants (BS) are surface-active molecules produced by microorganisms. For several decades they have attracted interest as promising alternatives to current petroleum-based surfactants. Aside from their green profile, they have remarkably low critical micelle concentrations, reduce the air/water surface tension to very low levels and are excellent emulsifiers, all of which make them comparable or superior to their synthetic counterparts. These remarkable physical properties derive from their more complex chemical structures in which hydrophilic and hydrophobic regions are not as clearly separated as chemical surfactants but have a more mosaic distribution of polarity as well as branched or circular structures...
September 30, 2016: Biochimica et Biophysica Acta
Nancy Gupta, Satish Vedi, Dennis Y Kunimoto, Babita Agrawal, Rakesh Kumar
Mycobacterium tuberculosis (Mtb), the bacterial cause of tuberculosis, is a leading infectious agent worldwide. The development of a new vaccine against Mtb is essential to control global spread of tuberculosis, since the current vaccine BCG is not very effective and antibiotic resistance is a serious, burgeoning problem. ESAT-6 is a secreted protein of Mtb, which is absent in BCG but has been implicated in inducing protective immunity against Mtb. Peptide based subunit vaccines are attractive due to their safety and high specificity in eliciting immune responses, but small synthetic peptides are usually not very immunogenic...
September 29, 2016: Vaccine
Stephen A Cochrane, Brandon Findlay, Alireza Bakhtiary, Jeella Z Acedo, Eva M Rodriguez-Lopez, Pascal Mercier, John C Vederas
Tridecaptin A1 (TriA1) is a nonribosomal lipopeptide with selective antimicrobial activity against Gram-negative bacteria. Here we show that TriA1 exerts its bactericidal effect by binding to the bacterial cell-wall precursor lipid II on the inner membrane, disrupting the proton motive force. Biochemical and biophysical assays show that binding to the Gram-negative variant of lipid II is required for membrane disruption and that only the proton gradient is dispersed. The NMR solution structure of TriA1 in dodecylphosphocholine micelles with lipid II has been determined, and molecular modeling was used to provide a structural model of the TriA1-lipid II complex...
October 11, 2016: Proceedings of the National Academy of Sciences of the United States of America
Milya Davlieva, Angel Tovar-Yanez, Kimberly DeBruler, Paul G Leonard, Michael R Zianni, Cesar A Arias, Yousif Shamoo
The cyclic antimicrobial lipopeptide daptomycin (DAP) triggers the LiaFSR membrane stress response pathway in enterococci and many other Gram-positive organisms. LiaR is the response regulator that, upon phosphorylation, binds in a sequence-specific manner to DNA to regulate transcription in response to membrane stress. In clinical settings, non-susceptibility to DAP by Enterococcus faecium is correlated frequently with a mutation in LiaR of Trp73 to Cys (LiaR(W73C)). We have determined the structure of the activated E...
September 23, 2016: Journal of Molecular Biology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"