Interference With Quorum-Sensing Signal Biosynthesis as a Promising Therapeutic Strategy Against Multidrug-Resistant Pathogens

Faced with the global health threat of increasing resistance to antibiotics, researchers are exploring interventions that target bacterial virulence factors. Quorum sensing is a particularly attractive target because several bacterial virulence factors are controlled by this mechanism. Furthermore, attacking the quorum-sensing signaling network is less likely to select for resistant strains than using conventional antibiotics. Strategies that focus on the inhibition of quorum-sensing signal production are especially attractive because the enzymes involved are expressed in bacterial cells but are not present in their mammalian counterparts. We review here various approaches that are being taken to interfere with quorum-sensing signal production via the inhibition of autoinducer-2 synthesis, PQS synthesis, peptide autoinducer synthesis, and N-acyl-homoserine lactone synthesis. We expect these approaches will lead to the discovery of new quorum-sensing inhibitors that can help to stem the tide of antibiotic resistance

Shedding some light over the floral metabolism by Arum Lily (Zantedeschia aethiopica) Spathe de novo transcriptome assembly

Zantedeschia aethiopica is an evergreen perennial plant cultivated worldwide and commonly used for ornamental and medicinal purposes including the treatment of bacterial infections. However, the current understanding of molecular and physiological mechanisms in this plant is limited, in comparison to other non-model plants. In order to improve understanding of the biology of this botanical species, RNA-Seq technology was used for transcriptome assembly and characterization. Following Z. aethiopica spathe tissue RNA extraction, high-throughput RNA sequencing was performed with the aim of obtaining both abundant and rare transcript data. Functional profiling based on KEGG Orthology (KO) analysis highlighted contigs that were involved predominantly in genetic information (37%) and metabolism (34%) processes. Predicted proteins involved in the plant circadian system, hormone signal transduction, secondary metabolism and basal immunity are described here. In silico screening of the transcriptome data set for antimicrobial peptide (AMP) – encoding sequences was also carried out and three lipid transfer proteins (LTP) were identified as potential AMPs involved in plant defense. Spathe predicted protein maps were drawn, and suggested that major plant efforts are expended in guaranteeing the maintenance of cell homeostasis, characterized by high investment in carbohydrate, amino acid and energy metabolism as well as in genetic information

Identification of the Active Principle Conferring Anti-Inflammatory and Antinociceptive Properties in Bamboo Plant

Early plants began colonizing earth about 450 million years ago. During the process of coevolution, their metabolic cellular pathways produced a myriad of natural chemicals, many of which remain uncharacterized biologically. Popular preparations containing some of these molecules have been used medicinally for thousands of years. In Brazilian folk medicine, plant extracts from the bamboo plant Guadua paniculata Munro have been used for the treatment of infections and pain. However, the chemical basis of these therapeutic effects has not yet been identified. Here, we performed protein biochemistry and downstream pharmacological assays to determine the mechanisms underlying the anti-inflammatory and antinociceptive effects of an aqueous extract of the G. paniculata rhizome, which we termed AqGP. The anti-inflammatory and antinociceptive effects of AqGP were assessed in mice. We identified and purified a protein (AgGP), with an amino acid sequence similar to that of thaumatins (~20 kDa), capable of repressing inflammation through downregulation of neutrophil recruitment and of decreasing hyperalgesia in mice. In conclusion, we have identified the molecule and the molecular mechanism responsible for the anti-inflammatory and antinociceptive properties of a plant commonly used in Brazilian folk medicine

Categorization of <i>Z. aethiopica</i> spathe transcriptome into KEGG biological categories.

<p>A. Total KEGG biological categories contigs distribution; B. Metabolism biological category distribution of contigs percentage.</p

Secondary Metabolism Pathways for <i>Zantedeschia aethiopica</i> assigned by KEGG Orthology (KO).

<p>Secondary Metabolism Pathways for <i>Zantedeschia aethiopica</i> assigned by KEGG Orthology (KO).</p

Final molecular dynamics scores for <i>Zantedeschia aethiopica</i> lipid transfer protein (LTP) docking with lipid ligands.

a<p>Data generated by comparing the structure at 0 ns and 50 ns.</p>b<p>The RMSD evolution along the time is available in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0090487#pone.0090487.s014" target="_blank">Figure S14</a>.</p>c<p>Excluding the polyproline tail, this value is reduced to 4.117.</p

Sequencing and assembly of <i>Zantedeschia aethiopica</i> transcriptome using Illumina HiSeq 2000.

<p>Sequencing and assembly of <i>Zantedeschia aethiopica</i> transcriptome using Illumina HiSeq 2000.</p

Lipid Transfer Proteins structural analysis.

<p>A. Multiple alignment of LTPs here identified. Conserved residues are green highlighted and the cysteine residues are in yellow. Final three-dimensional structures of LTPs with ligands before and after 50 ns of molecular dynamics are illustrated at B. Za-LTP1 + Oleic acid initial; C. Za-LTP1 + Oleic acid final; D. Za-LTP2 + Palmitoleic acid initial; E. Za-LTP2 + Palmitoleic acid final; F. Za-LTP3 + Alpha-Linoleic acid intial and G. Za-LTP3 + Alpha-linoleic acid final.</p

Plant-pathogen interaction basal immunity expression at <i>Z. aethiopica</i> spathe.

<p>e. expression; +u. ubiquitination; +p. phosphorylation; -p. dephosphorilation; x. dissociation; →. activation; ——. direct effect; –. inhibition. Molecules identified in this study are highlighted with grey shadow.</p