Vol 53, No 1 (2019)

Streptomyces albus J1074 is one of the most popular chassis for heterologous expression of actinobacterial biosynthetic gene clusters (BGCs). Considerable efforts are invested into understanding all the physiological and genetic aspects of secondary metabolism of J1074 in order to maximize the expression of heterologous BGCs. It has to be noted that the J1074 genome itself is home to numerous (>20) BGCs, whose expression varies widely. Therefore, the identification of the factors limiting the expression of J1074 BGCs might help improve this strain for heterologous expression purposes. As first steps towards this goal, herein we describe the secondary metabolome of J1074 in liquid medium SG2, previously shown by us to support the production of antibacterial and antifungal compounds. We compare the results of metabolomic studies with the transcriptome of J1074 in SG2 after 60 h of growth. Results of our studies are discussed in the context of current knowledge on the J1074 transcriptome and metabolome data.

Two Rapana venosa (R. venosa) samples representing different age groups from the same biotope (Odes’ka zatoka) were compared, using allozyme analysis, by their genetic structure. The genotypes were tested at 19 loci of nine enzymes. The genepool of the collected R. venosa samples was generally characterized by genetic disequilibrium and the elevated level of actual heterozygosity at the studied polymorphic loci (on average, at 16–18%). Sexually mature mollusk generations belonging to different age groups from the same biotope had a comparably lower relatedness between each other than the mollusk samples from different aquatic areas of the Black Sea. However, the genetic distance between the studied R. venosa groups was at the level of local populations in all cases. The analysis of the contribution made by evolutionary factors has shown the leading role of migrations in the formation of the R. venosa genepool in the northern part of the Black Sea.

Cell transplantation is a modern strategy for injured heart tissues regeneration. One of the promising sources for the generation of cardiomyocytes is embryonic stem cells (ESCs) and induced pluripotent stem cells iPSCs genetically modified murine ESC and iPSC lines expressing green fluorescent protein (GFP) under the control of the cardiospecific α-myosin heavy chain (MHC) promoter were used for the research; differentiation was carried out in a suspension culture with constant stirring. The effect of dimethyl sulfoxide (DMSO) on the processes of differentiation of pluripotent stem cells (PSCs) towards cardiomyocytes was studied both at the stage of mesoderm cells formation and at the stage of the cardiomyocytes progenitors formation. Optimal term of DMSO application into the culture was determined. It has been established that the addition of DMSO from the 5th day until the 9th day of cultivation increased the cardiomyocyte differentiation efficiency by one and a half times.

The hemiclonal structure of the Pelophylax esculentus-ridibundus hybrid form from the Pripyat, Dniester, and Southern Boug river basins is analyzed. The interbasin and interpopulation differences in the inherited genome variation level are demonstrated. The genetic diversity level of the P. esculentus-ridibundus inherited genome in the Pripyat basin is significantly lower than in the other two basins. Monoclonal populations of this hybrid form have been identified only in the Pripyat basin. There were no significant differences in the genetic variability level of this hybrid form between the populations of the Dniester and Southern Boug basins. The relationship between the variability level of the inherited genome of the hybrid form and the potentially possible multiple hybridization of parental species is analyzed.

To the best of our knowledge this is the first study regarding the reporting of B chromosomes in this plant species. During the meiotic study of Trachyspermum ammi (L.) Sprague, maximum two B chromosomes were reported in diploid plants which were retained in induced autotetraploid after the treatment of 0.2% colchicine at seedling stage. In the present study, the meiotic behaviour of B-chromosomes was analyzed in Trachyspermum ammi (L.) Sprague. The presence of B chromosomes and their number in the plant species of higher ploidy level is controversial. The existence of B chromosomes in polyploids varies from species to species. In the present case, no change has been observed in the number of B chromosomes despite the duplication of A chromosomes in autotetraploid plant. The unaffected number of B chromosomes represents their peculiar behaviour of inheritance. The plant species show adaptive mechanism for their retention in population. In the present study, significant changes (p < 0.05) have been observed in the chiasma frequency and pollen fertility of both diploid carrier plant as compare to non-carrier ones. Furthermore, the chromosomal associations have also been considered with observed number of B chromosomes in autotetraploid carrier plant. In autotetraploid carrier plant, the frequencies of multivalents were found to be quite low in comparison to diploid carrier plant.

One of the premium qualities of Phosphate solubilizing bacteria is to solubilize insoluble phosphorus to make it available for plant roots to be engrossed. To check the ability for phosphate solubilization, production of indole acetic acid, antagonistic activity against fungal pathogen and intrinsic antibiotic resistance phosphorous solubilizing bacterial isolates were isolated and screened. In total, 12 PSB were found rod shaped cells being gram negative. Different levels of antibiotic resistance were observed by rhizobacterial isolates against four antibiotics (Ampicillin, Kanamycin, Tetracycline and Streptomycin 25, 30, 30 and 10 μg/mL respectively). The isolates S7 and S20 showed antifungal activity against Fusarium oxysporum. Conversion of insoluble phosphorous Ca₃(PO₄) into IAA was observed by all PSB Isolates. Two phosphorous solubilizing bacterial isolates sequences were submitted in NCBI database. Conclusively, good antifungal activity with greater ability to solubilize insoluble phosphorus can be achieved by combine application of rhizobacterial isolates with S22. Further, it is an eco-friendly and cost effective strategy to improve crop production.