Genome Size, Cytotype Diversity and Reproductive Mode Variation of Cotoneaster integerrimus (Rosaceae) from the Balkans

Cotoneaster integerrimus represents a multiploid and facultative apomictic system of widely distributed mountain populations. We used flow cytometry to determine genome size, ploidy level, and reproduction mode variation of the Balkan populations, supplemented by analysis of nuclear microsatellites in order to address: (i) geographic distribution and variation of cytotypes among the populations; (ii) variation of reproduction mode and the frequency of sexuality; (iii) pathways of endosperm formation among the sampled polyploids and their endosperm balance requirements; (iv) genotypic diversity and geographic distribution of clonal lineages of polyploids. The prevalence of apomictic tetraploid cytotype followed by sexual diploids and extremely rare triploids was demonstrated. This prevalence of tetraploids affected the populations’ structure composed from clonal genotypes with varying proportions. The co-occurrence of diploids and tetraploids generated higher cytotype, reproductive mode, and genotypic diversity, but mixed-ploidy sites were extremely rare. The endosperm imbalance facilitates the development and the occurrence of intermediate triploids in mixed-ploidy populations, but also different tetraploid lineages elsewhere with unbalanced endosperm. All these results showed that the South European populations of C. integerrimus have higher levels of cytotype and reproductive diversity compared to the Central European ones. Therefore, the South European populations can be considered as a potential reservoir of regional and global diversity for this species

Synthesis, characterization, antimicrobial activity and DFT study of some novel Schiff bases

Two new Schiff bases derived from L-cysteine and substituted benzaldehyde were synthesized: the compound 1 [2-((2-chlorobenzylidene) amino)-3-mercaptopropanoic acid] and the compound 2 [3-mercapto-2-((2-methoxybenzylidene) amino) propanoic acid]. Their structures were confirmed by experimental FT-IR, NMR (1H, 13C), and theoretical methodology DFT (density functional theory). DFT calculations were based on global chemical reactivity indices calculated using the B3LYP/6–31G*, B3LYP/6–31G**, and B3LYP/6–31+G* theory levels. Experimentally and theoretically obtained values for FT-IR and NMR (1H, 13C) of test compounds showed good agreement. The reactivity descriptors of B3LYP (E, EHOMO, ELUMO, dipole moment, ∆ɛ, μ, η, ω) were calculated to predict the stability of newly synthesized compounds. The microbiological activity of the compounds was tested on several Gram-positive bacteria: Staphylococcus aureus, Bacillus subtilis, Clostridium sporogenes, Microccocus luteus and Microccocus flavus. The following Gram-negative bacteria were used to test the compounds: Escherichia coli, Pseudomonas aeruginosa Proteus hauseri, Klebsiella pneumoniae, Salmonella enterica subsp. enterica serovar Enteritidis. Also, the activity on the following yeasts was examined: Candida albicans, Saccharomyces cerevisiae and fungal strain Aspergillus brasilliensis. The Schiff base with chlorine in the structure (the compound 1) has the best antimicrobial action against all tested microorganisms. The selected quantum chemical descriptors calculated for the compounds 1 and 2 have a close relationship with the antimicrobial activity