Electropolymerized-molecularly imprinted polymers (E-MIPS) as sensing elements for the detection of dengue infection.

A straightforward in situ detection method for dengue infection was demonstrated through the molecular imprinting of a dengue nonstructural protein 1 (NS1) epitope into an electropolymerized molecularly imprinted polyterthiophene (E-MIP) film sensor. The key enabling step in the sensor fabrication is based on an epitope imprinting strategy, in which short peptide sequences derived from the original target molecules were employed as the main template for detection and analysis. The formation of the E-MIP sensor films was facilitated using cyclic voltammetry (CV) and monitored in situ by electrochemical quartz crystal microbalance (EC-QCM). Surface properties were analyzed using different techniques including atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and polarization modulation-infrared reflection-adsorption (PM-IRRAS). The standard calibration curve (R = 0.9830) was generated for the detection of the epitope, Ac-VHTWTEQYKFQ-NH2, with a linear range of 0.2 to 30 µg/mL and detection limit of 0.073 µg/mL. A separate calibration curve (R = 0.9786) was obtained using spiked buffered solutions of dengue NS1 protein, which resulted in a linear range of 0.2 to 10 µg/mL and a detection limit of 0.056 µg/mL. The fabricated E-MIP sensor exhibited long-term stability, high sensitivity, and good selectivity towards the targeted molecules. These results indicated that the formation of the exact and stable cavity imprints in terms of size, shape, and functionalities was successful. In our future work, we aim to use our E-MIP sensors for NS1 detection in real-life samples such as serum and blood.

Effects of truncation of the peptide chain on the secondary structure and bioactivities of palmitoylated anoplin.

Anoplin (GLLKRIKTLL-NH2) is of current interest due to its short sequence and specificity towards bacteria. Recent studies on anoplin have shown that truncation and acylation compromises its antimicrobial activity and specificity, respectively. In this study, truncated analogues (pal-ano-9 to pal-ano-5) of palmitoylated anoplin (pal-anoplin) were synthesized to determine the effects of C-truncation on its bioactivities. Moreover, secondary structure of each analogue using circular dichroism (CD) spectroscopy was determined to correlate with bioactivities. Interestingly, pal-anoplin, pal-ano-9 and pal-ano-6 were helical in water, unlike anoplin. In contrast, pal-ano-8, pal-ano-7 and pal-ano-5, with polar amino acid residues at the C-terminus, were random coil in water. Nevertheless, all the peptides folded into helical structures in 30% trifluoroethanol/water (TFE/H2O) except for the shortest analogue pal-ano-5. Hydrophobicity played a significant role in the enhancement of activity against bacteria E. coli and S. aureus as all lipopeptides including the random coil pal-ano-5 were more active than the parent anoplin. Meanwhile, the greatest improvement in activity against the fungus C. albicans was observed for pal-anoplin analogues (pal-ano-9 and pal-ano-6) that were helical in water. Although, hydrophobicity is a major factor in the secondary structure and antimicrobial activity, it appears that the nature of amino acids at the C-terminus also influence folding of lipopeptides in water and its antifungal activity. Moreover, the hemolytic activity of the analogues was found to correlate with hydrophobicity, except for the least hemolytic, pal-ano-5. Since most of the analogues are more potent and shorter than anoplin, they are promising drug candidates for further development.

Stability parameters and performance of interregional crosses in durum wheat (Triticum durum Desf.).

Twelve durum wheat varieties originating from 3 ecologically diverse regions and their 48 intergroup crosses were evaluated for stability of performance with respect to grain yield and certain component traits. The linear component of the genotype-environment interaction was revealed for grain yield, 100-grain weight and plant height, non-linear for tiller number whereas for grains per spike both components were equally important. However, except for tiller number, the linear component appeared to be contributing to a large extent towards the prevalent interactions. NP 404, Bijaga Yellow and Giorgio VZ 331 depicted stable performance for grain yield. However, considering all the attributes, the parents NP 404, Bijaga Yellow, Anhinga 's' and Mexicali 75 and hybrids NP 401 x Mexicali 75, NP 404 x Anhinga 's', NP 412 x Mexicali 75, NP 404 x Gerardo VZ 466 and Anhinga 's' x Capeiti appeared promising. The Mexican group as a whole exhibited a more stable performance than the other two evaluated groups. Compensating shift among the component characters was evident in the case of parents as well as hybrids and stability of performance appeared to be under genetic control. Effective utilization of these two aspects through introduction in otherwise desirable varieties has been advocated.

7-Methylguanine specific tRNA-methyltransferase from Escherichia coli.

A 7-methylguanine (m7G) specific tRNA methyltransferase from E. coli MRE 600 was purified about 1000 fold by affinity chromatography on Sepharose bound with normal E. coli tRNA. The purified enzyme catalyzes exclusively the formation of m7G in submethylated bulk tRNA of E. coli K12 met- rel-. The purified enzyme transfers the methyl group from S-adenosyl-methionine to initiator tRNA of B. subtilis and 0.8 moles m7G residues are formed per mole tRNA. It is suggested that the enzyme specifically recognizes the extra arm unpaired guanylate residue.

Purification and characterization of tRNAMet-f, tRNAPhe and tRNATyr2 from Baccillus subtilis.

Three tRNAs specific for methionine, phenylalanine and tyrosine were isolated from the total tRNA of Bacillus subtilis by chromatographic procedures using BD-cellulose and reversed-phase (5) chromatography. The acceptor activities of the purified tRNAs are 1160, 1260 and 1320 pmoles per A260nm unit for tRNAMetf, tRNAPhe and tRNATyr2 respectively. In tRNAMetf and tRNAPhe ribothymidine, pseudouridine and dihydrouridine are present, in addition, in tRNAPhe 7-methyguanosine and a 2'-O-methylated nucleoside were found. The modified nucleosides of tRNATyr2 are ribothymidine, pseudouridine, dihydrouridine, 4-thiouridine and 1-methyladenosine. The results suggest the presence of 2-methylthio-N6(delta 2-isopentenyl)adenosine in tRNAPhe and tRNATyr2. The thermal denaturation profiles of the three tRAN species are presented.