scholarly journals Carotenogenesis of Staphylococcus aureus: new insights and impact on membrane biophysical properties

2020 ◽  
Author(s):  
Gerson-Dirceu López ◽  
Elizabeth Suesca ◽  
Gerardo Álvarez-Rivera ◽  
Adriana Rosato ◽  
Elena Ibáñez ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biosynthetic Pathway ◽  
Acyl Chain ◽  
Biophysical Properties ◽  
Knock Out ◽  
Chain Order ◽  
Biophysical Study ◽  
Antimicrobial Peptide Resistance ◽  
And Shifts ◽  
First Time

AbstractStaphyloxanthin (STX) is a saccharolipid derived from a carotenoid in Staphylococcus aureus involved in oxidative-stress tolerance and antimicrobial peptide resistance. In this work, a targeted metabolomics and biophysical study was carried out on native and knock-out S. aureus strains to investigate the biosynthetic pathways of STX and related carotenoids. Identification of 34 metabolites at different growth phases (8, 24 and 48h), reveal shifts of carotenoid populations during progression towards stationary phase. Six of the carotenoids in the STX biosynthetic pathway and three menaquinones (Vitamin K2) were identified in the same chromatogram. Furthermore, other STX homologues with varying acyl chain structures reported herein for the first time, which reveal the extensive enzymatic activity of CrtO/CrtN. Fourier Transform infrared spectroscopy show that STX increases acyl chain order and shifts the cooperative melting of the membrane indicating a more rigid lipid bilayer. This study shows the diversity of carotenoids in S. aureus, and their influence on membrane biophysical properties.

scholarly journals Carotenogenesis of Staphylococcus aureus: New insights and impact on membrane biophysical properties

2021 ◽  
pp. 158941
Author(s):  
Gerson-Dirceu López ◽  
Elizabeth Suesca ◽  
Gerardo Álvarez-Rivera ◽  
Adriana E. Rosato ◽  
Elena Ibáñez ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biophysical Properties

scholarly journals Biosynthesis of anandamide and N-palmitoylethanolamine by sequential actions of phospholipase A2 and lysophospholipase D

2004 ◽  
Vol 380 (3) ◽  
pp. 749-756 ◽  
Author(s):  
Yong-Xin SUN ◽  
Kazuhito TSUBOI ◽  
Yasuo OKAMOTO ◽  
Takeharu TONAI ◽  
Makoto MURAKAMI ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Brain Homogenate ◽  
Wide Distribution ◽  
Rat Tissues ◽  
Lysophospholipase D ◽  
Pla2 Enzyme ◽  
First Time ◽  
Hydrolysis Of ◽  
The Brain

Anandamide (an endocannabinoid) and other bioactive long-chain NAEs (N-acylethanolamines) are formed by direct release from N-acyl-PE (N-acyl-phosphatidylethanolamine) by a PLD (phospholipase D). However, the possible presence of a two-step pathway from N-acyl-PE has also been suggested previously, which comprises (1) the hydrolysis of N-acyl-PE to N-acyl-lysoPE by PLA1/PLA2 enzyme(s) and (2) the release of NAEs from N-acyllysoPE by lysoPLD (lysophospholipase D) enzyme(s). In the present study we report for the first time the characterization of enzymes responsible for this pathway. The PLA1/PLA2 activity for N-palmitoyl-PE was found in various rat tissues, with the highest activity in the stomach. This stomach enzyme was identified as group IB sPLA2 (secretory PLA2), and its product was determined as N-acyl-1-acyl-lysoPE. Recombinant group IB, IIA and V of sPLA2s were also active with N-palmitoyl-PE, whereas group X sPLA2 and cytosolic PLA2α were inactive. In addition, we found wide distribution of lysoPLD activity generating N-palmitoylethanolamine from N-palmitoyl-lysoPE in rat tissues, with higher activities in the brain and testis. Based on several lines of enzymological evidence, the lysoPLD enzyme could be distinct from the known N-acyl-PE-hydrolysing PLD. sPLA2-IB dose dependently enhanced the production of N-palmitoylethanolamine from N-palmitoyl-PE in the brain homogenate showing the lysoPLD activity. N-Arachidonoyl-PE and N-arachidonoyl-lysoPE as anandamide precursors were also good substrates of sPLA2-IB and the lysoPLD respectively. These results suggest that the sequential actions of PLA2 and lysoPLD may constitute another biosynthetic pathway for NAEs, including anandamide.

scholarly journals Finding of Agr Phase Variants in Staphylococcus aureus

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Vishal Gor ◽  
Aya J. Takemura ◽  
Masami Nishitani ◽  
Masato Higashide ◽  
Veronica Medrano Romero ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Phase Variation ◽  
Accessory Gene ◽  
Content Type ◽  
Accessory Gene Regulator ◽  
Immune Mediated ◽  
A Minor ◽  
First Time ◽  
Phase Variants

ABSTRACT Staphylococcus aureus is an important human pathogen whose success is largely attributed to its vast arsenal of virulence factors that facilitate its invasion into, and survival within, the human host. The expression of these virulence factors is controlled by the quorum sensing accessory gene regulator (Agr) system. However, a large proportion of clinical S. aureus isolates are consistently found to have a mutationally inactivated Agr system. These mutants have a survival advantage in the host but are considered irreversible mutants. Here we show, for the first time, that a fraction of Agr-negative mutants can revert their Agr activity. By serially passaging Agr-negative strains and screening for phenotypic reversion of hemolysis and subsequent sequencing, we identified two mutational events responsible for reversion: a genetic duplication plus inversion event and a poly(A) tract alteration. Additionally, we demonstrate that one clinical Agr-negative methicillin-resistant S. aureus (MRSA) isolate could reproducibly generate Agr-revertant colonies with a poly(A) tract genetic mechanism. We also show that these revertants activate their Agr system upon phagocytosis. We propose a model in which a minor fraction of Agr-negative S. aureus strains are phase variants that can revert their Agr activity and may act as a cryptic insurance strategy against host-mediated stress. IMPORTANCE Staphylococcus aureus is responsible for a broad range of infections. This pathogen has a vast arsenal of virulence factors at its disposal, but avirulent strains are frequently isolated as the cause of clinical infections. These isolates have a mutated agr locus and have been believed to have no evolutionary future. Here we show that a fraction of Agr-negative strains can repair their mutated agr locus with mechanisms resembling phase variation. The agr revertants sustain an Agr OFF state as long as they exist as a minority but can activate their Agr system upon phagocytosis. These revertant cells might function as a cryptic insurance strategy to survive immune-mediated host stress that arises during infection.

scholarly journals CHEMICAL CONSTITUENTS AND BIOACTIVITY OF Codium amplivesiculatum SETCHELL N. L.GARDNER (CHLOROPHYTA; BRYOPSIDALES)

2013 ◽  
Vol 28 (2) ◽  
pp. 1
Author(s):  
A. Marín -Álvarez ◽  
J. I. Murrillo -Álvarez ◽  
M. Muñoz -Ochoa ◽  
G. M. Molina -Salinas
Keyword(s):  
Staphylococcus Aureus ◽  
Silica Gel ◽  
Vibrio Parahaemolyticus ◽  
Marine Alga ◽  
Chemical Constituents ◽  
Ethanol Extract ◽  
Solvent Mixtures ◽  
Bioactive Substances ◽  
First Time ◽  
Tuberculosis Activity

In search of bioactive substances from Mexican marine organisms, crude ethanol-extract from the marine alga Codium amplivesiculatum was fractionated in chromatographic columns of silica gel at 60 Å (230-400 mesh) using solvent mixtures of increasing polarity. All the fractions were submitted to antibacterial assays. The major metabolite from an anti-tuberculosis fraction (MIC = 100 μg mL–1) was purified and identified as 1-octodecanol (1). The anti-tuberculosis activity was attributed to 1 with bases in previous reports. In addition, clerosterol (2) was obtained by crystallization from an active fraction against Staphylococcus aureus and Vibrio parahaemolyticus (MIC = 125 and 250 μg mL–1, respectively). Both structures were established by interpretation and comparison of infrared and 1H NMR spectroscopic data. In contrast with other studies, 2 showed a non-significant cytotoxicity against the cell line PC-3 (% GI = 21.05 ± 0.3 at 50 μg mL–1). To our knowledge, these metabolites are reported for the first time from C. amplivesiculatum, and this is one of very rare reports of saturated long-chain alcohols isolated from chlorophytes. Constituyentes químicos y bioactividad de Codium amplivesiculatum Con el propósito de descubrir sustancias bioactivas a partir de organismos marinos encontrados en México, se fraccionó el extracto crudo etanólico de Codium amplivesiculatum en columnas cromatográficas de sílica gel 60 Å (230-400 de malla) utilizando mezclas de solventes de polaridad creciente. Todas las fracciones se sometieron a ensayos antibacterianos. El principal metabolito de la fracción activa antituberculosis (MIC = 100 μg mL-1), fue purificado e identificado como 1-octodecanol (1). La actividad antituberculosis, basada en reportes previos, se atribuyó al compuesto 1. Además, se obtuvo clerosterol (2) por cristalización de una fracción activa frente a Staphylococcus aureus y Vibrio parahaemolyticus (MIC = 125 y 250 μg mL-1, respectivamente). Las dos estructuras fueron inferidas mediante interpretación y comparación de datos obtenidos por espectroscopía de IR-ATR y 1H RMN. En contraste con otros estudios, el compuesto 2 mostró una citotoxicidad no significativa contra la línea celular PC-3 (% IC = 21.05 ± 0.3 a 50 μg mL–1). Hasta donde sabemos, estos metabolitos se reportan por primera vez en C. amplivesiculatum y 1-octadecanol es un reporte muy raro de alcohol de cadena larga aislado de clorofitas.

scholarly journals An efficient Nb-modified BiVO4 film for photo-induced bacterial inactivation and photocatalytic removal of organic pollutants

2018 ◽  
Vol 42 (8) ◽  
pp. 5664-5667
Author(s):  
Olivier Monfort ◽  
Ewa Dworniczek ◽  
Leonid Satrapinskyy ◽  
Alicja Seniuk ◽  
Daniela Nyblova ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Organic Pollutants ◽  
Bacterial Inactivation ◽  
Methicillin Resistant ◽  
Photocatalytic Removal ◽  
First Time

For the first time, Methicillin-resistant Staphylococcus aureus (MRSA) was inactivated using a Nb-modified BiVO4 photocatalyst.

scholarly journals The Antimicrobial Peptide Temporin G: Anti-Biofilm, Anti-Persister Activities, and Potentiator Effect of Tobramycin Efficacy Against Staphylococcus aureus

2020 ◽  
Vol 21 (24) ◽  
pp. 9410
Author(s):  
Bruno Casciaro ◽  
Maria Rosa Loffredo ◽  
Floriana Cappiello ◽  
Guendalina Fabiano ◽  
Luisa Torrini ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Human Keratinocytes ◽  
Skin Infections ◽  
Positive Bacterium ◽  
Persister Cells ◽  
Dividing Cells ◽  
Adverse Environmental Conditions ◽  
Bacterial Skin Infections ◽  
First Time

Bacterial biofilms are a serious threat for human health, and the Gram-positive bacterium Staphylococcus aureus is one of the microorganisms that can easily switch from a planktonic to a sessile lifestyle, providing protection from a large variety of adverse environmental conditions. Dormant non-dividing cells with low metabolic activity, named persisters, are tolerant to antibiotic treatment and are the principal cause of recalcitrant and resistant infections, including skin infections. Antimicrobial peptides (AMPs) hold promise as new anti-infective agents to treat such infections. Here for the first time, we investigated the activity of the frog-skin AMP temporin G (TG) against preformed S. aureus biofilm including persisters, as well as its efficacy in combination with tobramycin, in inhibiting S. aureus growth. TG was found to provoke ~50 to 100% reduction of biofilm viability in the concentration range from 12.5 to 100 µM vs ATCC and clinical isolates and to be active against persister cells (about 70–80% killing at 50–100 µM). Notably, sub-inhibitory concentrations of TG in combination with tobramycin were able to significantly reduce S. aureus growth, potentiating the antibiotic power. No critical cytotoxicity was detected when TG was tested in vitro up to 100 µM against human keratinocytes, confirming its safety profile for the development of a new potential anti-infective drug, especially for treatment of bacterial skin infections.

scholarly journals Lipoprotein N-Acylation in Staphylococcus aureus Is Catalyzed by a Two-Component Acyl Transferase System

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
John H. Gardiner ◽  
Gloria Komazin ◽  
Miki Matsuo ◽  
Kaitlin Cole ◽  
Friedrich Götz ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Envelope ◽  
Opportunistic Pathogen ◽  
Structural Heterogeneity ◽  
Cysteine Residue ◽  
Acyl Transfer ◽  
Acyl Transferase ◽  
Content Type ◽  
Tailoring Enzymes ◽  
And Shifts

ABSTRACT Bacterial lipoproteins (Lpps) are a class of membrane-associated proteins universally distributed among all bacteria. A characteristic N-terminal cysteine residue that is variably acylated anchors C-terminal globular domains to the extracellular surface, where they serve numerous roles, including in the capture and transport of essential nutrients. Lpps are also ligands for the Toll-like receptor 2 (TLR2) family, a key component of the innate immune system tasked with bacterial recognition. While Lpp function is conserved in all prokaryotes, structural heterogeneity in the N-terminal acylation state is widespread among Firmicutes and can differ between otherwise closely related species. In this study, we identify a novel two-gene system that directs the synthesis of N-acylated Lpps in the commensal and opportunistic pathogen subset of staphylococci. The two genes, which we have named the lipoprotein N-acylation transferase system (Lns), bear no resemblance to previously characterized N-terminal Lpp tailoring enzymes. LnsA (SAOUHSC_00822) is an NlpC/P60 superfamily enzyme, whereas LnsB (SAOHSC_02761) has remote homology to the CAAX protease and bacteriocin-processing enzyme (CPBP) family. Both LnsA and LnsB are together necessary and alone sufficient for N-acylation in Staphylococcus aureus and convert the Lpp chemotype from diacyl to triacyl when heterologously expressed in Listeria monocytogenes. Acquisition of lnsAB decreases TLR2-mediated detection of S. aureus by nearly 10-fold and shifts the activated TLR2 complex from TLR2/6 to TLR2/1. LnsAB thus has a dual role in attenuating TLR2 signaling in addition to a broader role in bacterial cell envelope physiology. IMPORTANCE Although it has long been known that S. aureus forms triacylated Lpps, a lack of homologs to known N-acylation genes found in Gram-negative bacteria has until now precluded identification of the genes responsible for this Lpp modification. Here, we demonstrate N-terminal Lpp acylation and chemotype conversion to the tri-acylated state is directed by a unique acyl transferase system encoded by two noncontiguous staphylococci genes (lnsAB). Since triacylated Lpps stimulate TLR2 more weakly than their diacylated counterparts, Lpp N-acylation is an important TLR2 immunoevasion factor for determining tolerance or nontolerance in niches such as in the skin microbiota. The discovery of the LnsAB system expands the known diversity of Lpp biosynthesis pathways and acyl transfer biochemistry in bacteria, advances our understanding of Lpp structural heterogeneity, and helps differentiate commensal and noncommensal microbiota.

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