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L Antonov

Publications and source records attributed to L Antonov.

5 recordsLinked to original sources
PubMed2000

Step by step filter based program for calculations of highly informative derivative curves

We have developed a microcomputer program, based on a recently described approach called step by step filter (SBSF), for calculation of derivative curves directly from spectra recorded as a function of wavelength. This program avoids the long wavelength attenuation featured at conventional method for derivative curves calculation, and in this extent could be very helpful for daily spectroscopy practice. The features of the SBSF program include: easy treatment of data through a windowed environment, calculating of both conventional and step by step filter derivatives, possibilities for selection of the mathematical conditions for smoothing and differentiation simultaneous plotting of the original curve and its derivative and a mouse pointer. Several examples from different branches of the molecular spectroscopy (absorption UV-VIS, CD and fluorescence) are provided and discussed in the terms of advantages of SBSF.

Journal Article↗
PubMed1998

Expression of an anther-specific chalcone synthase-like gene is correlated with uninucleate microspore development in Nicotiana sylvestris.

Two cDNA clones, specifically expressed in Nicotiana sylvestris anthers during uninucleate microspore development, were isolated using a subtractive hybridization approach. Sequence analysis showed that one of them, NSCHSLK, displayed a high level of similarity to several anther-specific chalcone synthase-like (CHSLK) proteins and an ORF from chromosome I of Arabidopsis thaliana. A lower, but significant, similarity to chalcone synthases and closely related enzymes (CHSRE) was also detected. The structure of the nschslk gene was found to be typical of the chalcone (chs)/stilbene (sts) synthase family. Expression of NSCHSLK mRNA was confined to microspores and tapetal cells. UV-irradiation or infection with Phytophthora parasitica var. nicotianae of transgenic Nicotiana benthamiana plants carrying a chimeric nschslk/GUS gene indicated that the nschslk promoter exhibits the same anther-specific, developmentally regulated expression pattern. Comparison of CHSRE and CHSLK polypeptide sequences revealed some important similarities and differences between the two groups. The data presented in this study, suggest that the anther-specific chslk genes represent a separate sub-family of plant polyketide synthases related to chs/sts in terms of gene structure, polypeptide sequence and the possible catalytic mechanism, but differing in substrate/product specificity. The putative role of CHSLK enzymes in anther development and particularly in exine synthesis is discussed.

Acyltransferases↗