Algal Biodiversity of Nine Megaliths in South-East Bulgaria.

This paper presents the first data on the biodiversity of lithophytic algae from Bulgarian megaliths obtained after the application of the direct sampling method, subsequent cultivation, and processing by light microscopy. A rich algal flora was found: 90 species and 1 variety of 65 genera from Cyanoprokaryota/Cyanobacteria (29 species, 13 genera), Chlorophyta (40 species and 1 variety, 38 genera), Streptophyta (5 species, 1 genus), and Ochrophyta (16 species, 13 genera). Among them were the globally rare (Chlorophyta), found for the first time in such lowland and warm habitats, and (Chlorophyta), for which this is the first finding in the country.

Is the First Genetically Proved Anatoxin A Producer in Bulgarian Lakes and Reservoirs.

The paper presents the first proof of planktonic cyanoprokaryote genus as an anatoxin A (ATX) producer in Bulgarian wetlands. The results from polymerase chain reaction (PCR) obtained from two summer sampling campaigns in 26 selected lakes and reservoirs demonstrated presence of the gene, responsible for ATX production in 21 strains of the genus. They were found in three waterbodies sampled in 2018 (coastal lake Vaya, coastal reservoir Poroy, inland reservoir Sinyata Reka) and in four waterbodies sampled in 2019 (inland reservoirs Duvanli, Koprinka, Plachidol 2, Sinyata Reka).

First Report on as a Potential Microviridin Producer in Bulgarian Waterbodies.

Bulgaria, situated on the Balkan Peninsula, is rich in small and shallow, natural and man-made non-lotic waterbodies, which are threatened by blooms of Cyanoprokaryota/Cyanobacteria. Although cyanotoxins in Bulgarian surface waters are receiving increased attention, there is no information on microviridins and their producers. This paper presents results from a phytoplankton study, conducted in August 2019 in three lakes (Durankulak, Vaya, Uzungeren) and five reservoirs (Duvanli, Mandra, Poroy, Sinyata Reka, Zhrebchevo) in which a molecular-genetic analysis (PCR based on the precursor gene and subsequent translation to amino acid alignments), combined with conventional light microscopy and an HPLC analysis of marker pigments, were applied for the identification of potential microviridin producers.

Morphological and Molecular Identification of Microcystin-Producing Cyanobacteria in Nine Shallow Bulgarian Water Bodies.

The paper presents results from the first application of polyphasic approach in studies of field samples from Bulgaria. This approach, which combined the conventional light microscopy (LM) and molecular-genetic methods (based on PCR amplified fragments of microcystin synthetase gene ), revealed that almost all microcystin-producers in the studied eutrophic waterbodies belong to the genus . During the molecular identification of toxin-producing strains by use of HEPF × HEPR pair of primers, we obtained 57 sequences, 56 of which formed 28 strains of spread in six clusters of the phylogenetic tree.

Investigations of cell morphology and reproduction in Ettl & Gärtner (Stephano-sphaerinia, Chlorophyta) by light- and WUDQVPLVVLRQ electron microscopy.

Cell division and reproduction of a cultivated strain of (Stephanosphaerinia clade) were studied by light- and transmission electron microscopy. Multinucleate cells were frequently observed allowing description of the cell structure and details of the reproduction process. Nuclear staining revealed the position of the multiple polymorphic nuclei between the chloroplast lobes.