Search results for "sort"

ANTI-STAPHYLOCOCCAL BIOFILM ACTIVITY OF NOVEL SORTASE A (SRTA) INHIBITORS

2013

Pathogenic staphylococci have an extraordinary ability to form biofilms. This characteristic is likely the most important virulence factor of staphylococci in the development of the chronic form of infectious diseases and in biomaterial associated infections (BAI). Staphylococcal biofilms are particularly dangerous because they are more resistant to host immune defence system and have a significantly increased tolerance to conventional antibiotics. There is undoubtedly an urgent need for novel treatments, strategies and anti-staphylococcal biofilm agents. The Sortase A (SrtA) transpeptidase is responsible for covalent anchoring to the cell wall of various surface proteins (FnbpA, FnbpB, Clf…

Magnaporthe oryzae as an expression host for the production of the unspecific peroxygenase AaeUPO from the basidiomycete Agrocybe aegerita.

2021

Abstract The filamentous fungus Magnaporthe oryzae has the potential to be developed as an alternative platform organism for the heterologous production of industrially important enzymes. M. oryzae is easy to handle, fast‐growing and unlike yeast, posttranslational modifications like N‐glycosylations are similar to the human organism. Here, we established M. oryzae as a host for the expression of the unspecific peroxygenase from the basidiomycete Agrocybe aegerita (AaeUPO). Note, UPOs are attractive biocatalysts for selective oxyfunctionalization of non‐activated carbon‐hydrogen bonds. To improve and simplify the isolation of AaeUPO in M. oryzae, we fused a Magnaporthe signal peptide for pr…

Targeting the Sortase A Transpeptidase to Tackle Gram-positive Pathogens

2013

The virulence factors include the cell-wall associated proteins called MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) that can promote the adhesion to host proteins, for example, the fibronectin that is very common in host tissues. The cellwall associated proteins are necessary for host colonization, invasion, immune evasion and biofilm formation [4]. The biofilms, multistratified bacterial communities that grow on a biological or artificial surface, are responsible for chronic infectious diseases and for device or biomaterial associated infections, and are more resistant to host immune defence system and to conventional antibiotics [5].

Improving distance based image retrieval using non-dominated sorting genetic algorithm

2015

Image retrieval is formulated as a multiobjective optimization problem.A multiobjective genetic algorithm is hybridized with distance based search.A parameter balances exploration (genetic search) or exploitation (nearest neighbors).Extensive comparative experimentation illustrate and assess the proposed methodology. Relevance feedback has been adopted as a standard in Content Based Image Retrieval (CBIR). One major difficulty that algorithms have to face is to achieve and adequate balance between the exploitation of already known areas of interest and the exploration of the feature space to find other relevant areas. In this paper, we evaluate different ways to combine two existing relevan…

Visual Cortex Performs a Sort of Non-linear ICA

2010

Here, the standard V1 cortex model optimized to reproduce image distortion psychophysics is shown to have nice statistical properties, e.g. approximate factorization of the PDF of natural images. These results confirm the efficient encoding hypothesis that aims to explain the organization of biological sensors by information theory arguments.

Modular Breath Analyzer (MBA): Introduction of a Breath Analyzer Platform Based on an Innovative and Unique, Modular eNose Concept for Breath Diagnos…

2021

Exhaled breath analysis for early disease detection may provide a convenient method for painless and non-invasive diagnosis. In this work, a novel, compact and easy-to-use breath analyzer platform with a modular sensing chamber and direct breath sampling unit is presented. The developed analyzer system comprises a compact, low volume, temperature-controlled sensing chamber in three modules that can host any type of resistive gas sensor arrays. Furthermore, in this study three modular breath analyzers are explicitly tested for reproducibility in a real-life breath analysis experiment with several calibration transfer (CT) techniques using transfer samples from the experiment. The experiment …

Enzymatic activity of circular sortase A under denaturing conditions: An advanced tool for protein ligation

2014

Abstract Staphylococcus aureus sortase A is a transpeptidase that is extensively used in various protein research applications. Sortase A is highly selective and does not require any cofactors for the catalysis of protein ligation and, importantly, can be produced in high yields. However, the primary disadvantage of this transpeptidase is its inability to access the recognition site within the highly structured regions of folded substrates. To overcome this problem, we developed an Escherichia coli expression system that produces milligram quantities of circularly closed sortase A; efficient enzyme cyclization was achieved by Synechocystis sp. PCC6803 intein-mediated post-translational spli…

Frontispiece: Hierarchy of Asymmetry at Work: Chain-Dependent Helix-to-Helix Interactions in Supramolecular Polymers

2018

Sorting of Enhanced Reference Raman Spectra of a Single Amino Acid Molecule

2014

In this contribution, we report the identification of the principal reference Raman spectra of a single cystein molecule. To that purpose, we design an active Surface Enhanced Raman Spectroscopy (SERS) template based on surfactant-less Chebyshev nanoparticles operating in a microfluidic platform. A principal component analysis is obtained from fluctuating spectra to sort the reference spectra of cystein. The assignment of Raman bands brings new insight into the conformation of an amino acid adsorbed onto gold nanoparticle.

Novel Sortase A Inhibitors to Counteract Gram-Positive Bacterial Biofilms

2019

Sortase A (SrtA) is a membrane enzyme responsible for the covalent anchoring of surface proteins on the cell wall of Gram-positive bacteria. Nowadays it is considered an interesting target for the development of new anti-infective drugs which aim to interfere with important Gram-positive virulence mechanisms. Along the years, we studied the anti-staphylococcal and anti-biofilm activity of some natural and synthetic polyhalogenated pyrrolic compounds, called pyrrolomycins. Some of them were active on Gram-positive pathogens at a μg/mL range of concentration (1.5-0.045 μg/mL) and showed a biofilm inhibition in the range of 50-80%. [1-3] In light of these encouraging results, herein we present…