An Evaluation of Four Phylogenetic Markers in Nostoc: Implications for Cyanobacterial Phylogenetic Studies at the Intrageneric Level

The success of some phylogenetic markers in cyanobacteria owes to the design of cyanobacteria-specific primers, but a few studies have directly investigated the evolution "behavior" of the loci. In this study, we performed a case study in Nostoc to evaluate rpoC1, hetR, rbcLX, and 16S rRNA-tRNA(Ile)-tRNA(Ala)-23S rRNA internal transcribed spacer (ITS) as phylogenetic markers. The results indicated that the gene trees of these loci are not congruent with the phylogeny based on 16S rRNA gene. The mechanisms contributing to the incongruence include randomized variation and recombination. As the results suggested, one should be careful to choose the molecular markers for phylogenetic reconstruction at the intrageneric level in cyanobacteria.

New progress of studies on semiconductor materials

This paper is a review of research and development on semiconductor materials, which covers main scientific activities in this field. The present status acid future prospects of studies on semiconductor materials, such as silicon crystals, GaAs related III-V compound semiconductor materials and GaAs, InP and silicon based quantum well and superlattice materials, quantum wires and quantum dots materials, microcavity and photonic crystals, materials for quantum computation and wide band gap materials, are briefly discussed.