Antibacterial and anticancer activities of acetone extracts from in vitro cultured lichen-forming fungi.

Background: Lichens that were used in traditional medicine for ages produce numerous secondary metabolites, however our knowledge about biological activities of substances secreted by separated bionts is scarce. The main objectives of this study were to isolate and find optimal conditions for the growth of mycelia from three common lichen-forming fungi, i.e.

Sulforaphene, an isothiocyanate present in radish plants, inhibits proliferation of human breast cancer cells.

Background: Isothiocyanates derived from the Brassicaceae plants possess chemopreventive and anticancer activities. One of them is sulforaphene (SF), which is abundant in Rhapanus sativus seeds. The underlying mechanism of its anticancer activity is still underexplored.

Selective inhibition of cancer cells' proliferation by compounds included in extracts from Baltic Sea cyanobacteria.

Cyanobacteria are a rich source of biologically active compounds used in pharmacology and biotechnology. Due to their high capacity of adaptation, which is reflected in the production of diverse metabolites, including toxins, these microorganisms are able to inhabit very different environments. In this work, water and ethanol extracts from 11 cyanobacterial strains derived from the Baltic Sea (Microcystis, Synechocystis, Leptolyngbya, Pseudanabaena, Lyngbya, Phormidium, Nodularia and Anabaena genera) were screened for anticancer activity.

A small, microRNA-size, ribonucleic acid regulating gene expression and development of Shiga toxin-converting bacteriophage Φ24Β.

A microRNA-size (20-nt long) molecule has been identified in Escherichia coli after induction of Shiga toxin-converting bacteriophage Φ24B. This small RNA, named 24B_1, is encoded in the lom-vb_24B_43 region of the phage genome, and apparently it is produced by cleavage of a larger transcript. A phage devoid of 24B_1 revealed decreased efficiency of lysogenization, quicker prophage induction after provoking the SOS response, higher efficiency of progeny phage production during the lytic cycle and less efficient adsorption on the host cells.

The most widespread problems in the function-based microbial metagenomics.

Metagenomics is a powerful tool to better understand the microbial niches, especially these from extreme habitats like oceans and seas, hot springs or deserts. However, one who is going to face the metagenomic studies should realize the challenges which might occur in the course of experiments. This manuscript indicates common problems in function-driven metagenomics, especially factors that influence gene expression are taken into account.

Sampling, metadata and DNA extraction - important steps in metagenomic studies.

Metagenomic studies have become increasingly popular. They allow for the estimation of biodiversity in complex populations. This diversity presents an enormous but largely unexpected genetic and biological pool and can be exploited for the recovery of novel genes, entire metabolic pathways and their products.

Different expression patterns of genes from the exo-xis region of bacteriophage λ and Shiga toxin-converting bacteriophage Ф24B following infection or prophage induction in Escherichia coli.

Lambdoid bacteriophages serve as useful models in microbiological and molecular studies on basic biological process. Moreover, this family of viruses plays an important role in pathogenesis of enterohemorrhagic Escherichia coli (EHEC) strains, as they are carriers of genes coding for Shiga toxins. Efficient expression of these genes requires lambdoid prophage induction and multiplication of the phage genome.

Small regulatory RNAs in lambdoid bacteriophages and phage-derived plasmids: Not only antisense.

Until recently, only two small regulatory RNAs encoded by lambdoid bacteriophages were known. These transcripts are derived from paQ and pO promoters. The former one is supposed to act as an antisense RNA for expression of the Q gene, encoding a transcription antitermination protein.

The use of fosmid metagenomic libraries in preliminary screening for various biological activities.

Background: It is generally believed that there are many natural sources of as yet unknown bioactive compounds with a high biotechnological potential. However, the common method based on the use of cell extracts in the preliminary screening for particular molecules or activities is problematic as amounts of obtained compounds may be low, and such experiments are hardly reproducible. Therefore, the aim of this work was to test whether a novel strategy to search for previously unknown biological activities can be efficient.

Genes from the exo-xis region of λ and Shiga toxin-converting bacteriophages influence lysogenization and prophage induction.

The exo-xis region, present in genomes of lambdoid bacteriophages, contains highly conserved genes of largely unknown functions. In this report, using bacteriophage λ and Shiga toxin-converting bacteriophage ϕ24Β, we demonstrate that the presence of this region on a multicopy plasmid results in impaired lysogenization of Escherichia coli and delayed, while more effective, induction of prophages following stimulation by various agents (mitomycin C, hydrogen peroxide, UV irradiation). Spontaneous induction of λ and ϕ24Β prophages was also more efficient in bacteria carrying additional copies of the corresponding exo-xis region on plasmids.

Metagenomic approach in the investigation of new bioactive compounds in the marine environment.

The marine environment is estimated to be one of the most significant sources of biological activity in the world. In the last few decades an increase in the research intensity conducted on marine microorganisms has been observed, which confirms the great potential of these organisms in the field of bioactive compounds' production. In order to efficiently use the natural resources of the marine environment, metagenomics can be applied.

Escherichia coli O104:H4 outbreak--have we learnt a lesson from it?

Shiga toxin-producing Escherichia coli (STEC) strains belong to the group of pathogens that cause bloody diarrhea and hemorrhagic colitis with often severe complications. The main problem with human pathogenic E. coli strains, including STEC, is a wide spectrum of phenotypes and clinical manifestations.