Chlorosomes are specific light-harvesting complexes of photosynthetic bacteria, made of aggregated bacteriochlorophyll and other photosynthetic pigments. They are able to absorb and transfer light energy with high efficiency, enabling chlorosome-equipped bacteria to survive in dark places. Structure and function of chlorosomes have been investigated by several methods which however do not allow to uncover molecular level of chlorosome organisation sufficiently. Therefore, in this work the measurement of direct light absorption on single isolated chlorosomes were done for the first time. The heterogenous inner structure was revealed indicating that the results reported so far have been negatively influenced by this type of structural disorder. The work published is therefore significant for further experiments and understanding the principles of chlorosome functioning, too.
Repetitive DNA makes up significant portions of higher plant nuclear genomes. Therefore, investigation of sequence composition, genome organization and evolution of the repetitive DNA is crucial for our understanding of fundamental processes driving plant genome evolution and function, as well as for potential genetic manipulation in crop species. Taking advantage of the next-generation sequencing technologies, we performed detailed characterization of repetitive DNA in three complex plant genomes using a set of novel bioinformatics tools that have been previously developed in our laboratory. The data obtained for the model dioecious plant Silene latifolia, tobacco (Nicotiana tabacum) and potato (Solanum tuberosum) genomes provided new insights into the role of repetitive DNA in various evolutionary processes, including differentiation of plant sex chromosomes or polyploidization.
Antiviral effect of tenofovir - antivirotic developed by prof. A. Holý - onto model plant DNA virus Cauliflower mosaic virus was evaluated. Six to nine weeks after tenofovir treatment of infected Brassica pekinensis, virus was not detectable by any routine molecular methods used. Detailled study showed, that tenofovir in plants is acting like nucleotide - basic DNA element. Therefore, the principle of its effect on plant DNA viruses is apparently similar as in the case of animal viruses: tenofovir blocks reproduction of virus by incorporating itself into virus DNA when replicating.
Using electron techniques we have determined and compared structure of the photosynthetic apparatus of brown algae X. debile. Structure of both photosystems I and II is similar to those of higher plants and green algae. New was the observation of the structure and aggregation light-harvesting antennae.
An RNA virus was discovered and isolated from the lupine plants showing mosaicism on the leaves. The genome of virus was sequenced and phylogenetic analyse suggested novel virus related with plum pox virus. Detailed analysis showed, that this virus can be regarded as a member of a newly described potyvirus species, for which the name Lupine mosaic virus (LuMV) is proposed.
Plant nuclease (protein cleaving nucleic acids, like DNA) TBN1from tomato has an anticancerogenic effects on human tumors. Using plant biotechnology, sufficient amount of TBN1 was prepared and crystallized. Crystalographic analysis revealed molecular structure of TBN1, enabling targeted modifications of this anticancerogenic compound and - thus - its better usability in human medicine.
Presence and characteristic of phytoplasma plasmid are not known too much. Two plasmids associated with two strains of „Candidatus phytoplasma asteris“ have been obtained from two plant species. Both the plasmids were sequenced and six, or five open reading frames were found, respectively, each having nucleotide compossition very similar to phytoplasmas. Frutheremore, a segment of one of plasmids was almost identical to part of phytoplasma genome suggesting strongly, that such a plasmids are made somehow from phytoplasma genome.
Coat protein genes of grapevine fanleaf virus local strains isolated in South-Moravia, Czech Republic were sequenced, and artificial coat protein gene was designed and synthesized that retains typical sequence features of local strains but is free of mRNA destabilizing sequences. Three variants of the synthetic gene were cloned into Agrobacterium plant expression vector and their function was tested after potato protoplasts transformation, assaying transient mRNA and coat protein production. Vitis vinifera rootstock cultivars were transformed with Agrobacterium tumefaciens LBA4404 carrying vectors with variants of the synthetic gene, using the meristematic bulk tissue method.