A lectin from Sesbania aculeata (Dhaincha) roots and its possible function

Proteomic analysis of irradiated lung tissue of mice using gel-based proteomic approach

PURPOSE

Exposure to radiation causes severe alterations of protein expression level inside the cell, thus it may influence the biological events and stress response. In the present investigation, we have demonstrated the effect of radiation on mice lung tissues.

MATERIALS AND METHODS

Two-dimensional gel electrophoresis (2-DE) coupled with MALDI-TOF/TOF was used to check the expression changes in lung proteome profile of strain 'A' female mice after exposure to lethal doses of gamma irradiation at different time periods (24 and 48 h). Identified proteins were analysed for their altered expression and were further validated by Western blotting and enzyme-linked immunosorbent assay (ELISA).

RESULTS

Nine significant differentially expressed proteins were identified from irradiated lungs tissues. The expression level of zinc finger protein was found to be up regulated at 24 h irradiation in comparison to 48 h irradiation.

CONCLUSIONS

Zinc finger protein may be considered as a radiation responsive protein. Alteration in its expression pattern may primarily affect binding specificity of the protein that can further result in the interference in transcriptional control of multiple stress responsive genes.

Effect of algae and plant lectins on planktonic growth and biofilm formation in clinically relevant bacteria and yeasts

This study aimed to evaluate the abilities of plant and algae lectins to inhibit planktonic growth and biofilm formation in bacteria and yeasts. Initially, ten lectins were tested on Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella oxytoca, Pseudomonas aeruginosa, Candida albicans, and C. tropicalis at concentrations of 31.25 to 250 μg/mL. The lectins from Cratylia floribunda (CFL), Vatairea macrocarpa (VML), Bauhinia bauhinioides (BBL), Bryothamnion seaforthii (BSL), and Hypnea musciformis (HML) showed activities against at least one microorganism. Biofilm formation in the presence of the lectins was also evaluated; after 24 h of incubation with the lectins, the biofilms were analyzed by quantifying the biomass (by crystal violet staining) and by enumerating the viable cells (colony-forming units). The lectins reduced the biofilm biomass and/or the number of viable cells to differing degrees depending on the microorganism tested, demonstrating the different characteristics of the lectins. These findings indicate that the lectins tested in this study may be natural alternative antimicrobial agents; however, further studies are required to better elucidate the functional use of these proteins.

Identification of novel autoantigen in the synovial fluid of rheumatoid arthritis patients using an immunoproteomics approach

Rheumatoid arthritis (RA) is a chronic, autoimmune and inflammatory joint disease with a poorly understood etiology. Despite widespread diagnostic use of anti-citrullinated protein antibodies and rheumatoid factor proteins there is a strong demand for novel serological biomarkers to improve the diagnosis this disease. The present study was aimed to identify novel autoantigens involved in rheumatoid arthritis (RA) pathogenesis through immune-proteomic strategy. Synovial fluid samples from clinically diagnosed RA patients were separated on two-dimensional gel electrophoresis (2-DE). Samples from patients with non-RA rheumatisms (osteoarthritis and trauma) were used as controls. Immunoreactive proteins were spotted by Western blotting followed by identification through Q-TOF mass spectrometer analysis. Forty Western blots were generated using plasma from ten individual RA patients and 33 reactive spots were identified, 20 from the high molecular weight (HMW) gel and 13 from the low molecular weight (LMW) gel. Among the 33 common immunogenic spots, 18 distinct autoantigens were identified, out of which 14 are novel proteins in this context. Expression analysis of five important proteins, vimentin, gelsolin, alpha 2 HS glycoprotein (AHSG), glial fibrillary acidic protein (GFAP), and α1B-glycoprotein (A1BG) by Western blot analysis using their specific antibodies revealed their higher expression in RA synovial fluid as compared to non-RA samples. Recombinantly expressed GFAP and A1BG protein were used to develop an in-house ELISA to quantify the amount of autoantibodies in the RA patients. RA patients revealed an increase in the expression of GFAP and A1BG in the plasma as compared to osteoarthritis patients. Therefore, GFAP and A1BG can be proposed as potential new autoantigens of diagnostic importance for RA subjects. Further characterization of these proteins in rheumatoid arthritis will be helpful in understanding the role of these proteins in the disease pathogenesis providing new diagnostic tool with better specificity and accurate detection of the disease.

Lectin from Canavalia brasiliensis seeds (ConBr) is a valuable biotechnological tool to stimulate the growth of Rhizobium tropici in vitro

To study the interactions between a Rhizobium tropici strain and lectins isolated from the seeds of Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr), a lectin fluorescence assay was performed. In addition, an experiment was designed to evaluate the effect of the two lectins on bacterial growth. Both lectins were found to bind to R. tropici cells, but the interactions were inhibited by D-mannose. Interestingly, only ConBr stimulated bacterial growth in proportion to the concentrations used (15.6–500 µg/mL), and the bacterial growth stimulation was inhibited by D-mannose as well. Structure/Function analyses by bioinformatics were carried out to evaluate the volume and carbohydrate recognition domain (CRD) configuration of ConA and ConBr. The difference of spatial arrangement and volume of CRD may indicate the variation between biological activities of both lectins. The results suggest that ConBr could be a promising tool for studies focusing on the interactions between rhizobia and host plants.

Cloning and functional characterization of a GNA-like lectin from Chinese Narcissus (Narcissus tazetta var. Chinensis Roem)

A full-length cDNA encoding Narcissus tazetta lectin (NTL) was isolated from Chinese narcissus (N. tazetta var. Chinensis Roem). The open reading frame (ORF) was 519 bp long and encoded 172 amino acids with a theoretical isoelectric point of 5.27 and a calculated molecular mass of 18.6 kDa. Conserved domain analysis indicated that it possessed three D-(+)-mannose-binding sites, presumed to be similar to those of Galanthus nivalis agglutinin (GNA)-like lectins. A recombinant (glutathione S-transferase) GST-NTL fusion protein of around 40 kDa was successfully synthesized in vitro. Lysates of cells expressing this recombinant protein exhibited significant hemagglutinating activity [418 hemagglutinating units (HU)], as did the purified protein (265 HU). Sugar specificity assays suggested that mannose is the only sugar that significantly inhibits this hemagglutinating activity, confirming that NTL is a member of the GNA-like lectin family. NTL is highly transcribed in flowers, leaves and roots, but less so in scales. However, similar levels of the NTL protein were observed in all four of these organs by western blotting. A fluorescent NTL-GFP (green fluorescent protein) fusion protein was found to be primarily localized in the vacuole of transformed onion epidermal cells, indicating that NTL may be a vacuolar storage protein. This is the first study in which the function of NTL has been examined and provides a considerable body of data concerning its physiological role in Chinese narcissus. The results obtained may be useful in the molecular engineering of plants with enhanced tolerance of biotic and abiotic stresses. Moreover, they may be relevant to medical applications of lectins.

Purification and mass spectrometric characterization of Sesbania aculeata (Dhaincha) stem lectin

A glucose specific lectin (STA) was isolated from Sesbania aculeata stem by using Sephadex G-50 affinity column chromatography. The lectin is a glycoprotein having 29 kDa subunit molecular weight. Two dimensional gel electrophoresis analysis revealed that the lectin existed in two isomeric forms with varied carbohydrate content as analyzed by high performance anion exchange chromatography-pulsed amperometric detector (HPAEC-PAD). Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) and N-terminal sequence (LDSLSFTYNNFE) analysis of this lectin showed 95% homology with stem lectin SL-I (accession no. AJ585523) from peanut plant. The nucleotide sequence of the lectin (STA) was submitted to the gene bank (accession no. EU263636).