Use of the de novo transcriptome analysis of silver-leaf nightshade (Solanum elaeagnifolium) to identify gene expression changes associated with wounding and terpene biosynthesis.

BACKGROUND: Solanum elaeagnifolium, an invasive weed of the Solanaceae family, is poorly studied although it poses a significant threat to crops. Here the analysis of the transcriptome of S. elaeagnifolium is presented, as a means to explore the biology of this species and to identify genes related to its adaptation to environmental stress. One of the basic mechanisms by which plants respond to environmental stress is through the synthesis of specific secondary metabolites that protect the plant from herbivores and microorganisms, or serve as signaling molecules. One important such group of secondary metabolites are terpenes. RESULTS: By next-generation sequencing, the flower/leaf transcriptome of S. elaeagnifolium was sequenced and de novo assembled into 75,618 unigenes. Among the unigenes identified, several corresponded to genes involved in terpene biosynthesis; these included terpene synthases (TPSs) and genes of the mevalonate (MVA) and the methylerythritol phosphate (MEP) pathways. Functional characterization of two of the TPSs showed that one produced the sesquiterpene (E)-caryophyllene and the second produced the monoterpene camphene. Analysis of wounded S. elaeagnifolium leaves has shown significant increase of the concentration of (E)-caryophyllene and geranyl linalool, two terpenes implicated in stress responses. The increased production of (E)-caryophyllene was matched to the induced expression of the corresponding TPS gene. Wounding also led to the increased expression of the putative 1-deoxy-D-xylulose-5-phosphate synthase 2 (DXS2) gene, a key enzyme of the MEP pathway, corroborating the overall increased output of terpene biosynthesis. CONCLUSIONS: The reported S. elaeagnifolium de novo transcriptome provides a valuable sequence database that could facilitate study of this invasive weed and contribute to our understanding of the highly diverse Solanaceae family. Analysis of genes and pathways involved in the plant's interaction with the environment will help to elucidate the mechanisms that underly the intricate features of this unique Solanum species.

Molecularly imprinted polymers for histamine recognition in aqueous environment.

Molecularly imprinted polymers (MIP) for histamine using methacrylic acid were developed and recognition mechanisms were thoroughly characterized for the first time in this study. The binding affinity of imprinted polymer with structurally related compounds was studied in organic and aqueous media, at various conditions. In organic media, MIP was found to bind histamine two and six times more than ranitidine and fluoxetine, respectively, whereas higher selectivity was observed in the case of dimentidene or disodium cromoglycate. The specific binding sites of MIP recognized histamine over L-histidine in aqueous conditions, while higher affinity for histamine compared to ranitidine, disodium cromoglycate, putrescine and to a putrescine analogue was observed. A combination of NMR and UV spectroscopy analyses for investigation of imprinting and recognition properties revealed that strong specific interactions between the functional monomer and histamine in the prepolymerization and in the aqueous solutions were probably responsible for histamine recognition. The preparation of histamine MIPs and elucidation of imprinting and recognition mechanism may serve as useful insight for future application of MIPs.