Özet:

Although genetic material is usually transmitted vertically between generations through equal or non-equal reproduction, great similarities in some chromosomes and genetic parts of non-family organisms indicate that there may be another way of transmission. The horizontal gene transfer (YGT), known as the mobility of genetic information between different organisms, has sudden or delayed effects on the recipient’s residence. One of the most notable mechanisms of YGT is the natural transformation (DT), a process in which cells receive free DNA from an extra-cellular environment and incorporate them into their chromosomes through homologous recombination. DT is widely preserved in many types of bacteria because it can promote the spread of resistant genes. Although it is known that many organisms perform YGT, the information about how organisms decide on the horizontally transmitted genetic material is limited. Here, I have studied the priority of choosing Bacillus subtilis with DT capacity among the different genetic sources offered under certain stress conditions. To test this, two DNA samples (E and C) with the same length but different series content were presented to B. subtilis under different stress environments (BK, BC, BE and BCE). The hypothesis was evaluated according to the results of the analysis of colonies formed on selective plates (pE, pC and pCE) after DT. The data obtained presented a strong positive correlation that during the DT bacteria have preferential priority depending on a stimulant. It can be said that bacteria tend to receive useful DNA parts in a particular environment, for example, when the conversion environment contains erythromycin (Eryt) as an inducer, the majority of colonies grow on pE plates instead of pC and pCE. Although the data significantly coincides with the claim that bacteria have a preferential priority to obtain free DNA during DT, more research is needed to strongly support the data and understand the phenomenon correctly.

Anahtar Kelimeler:

Özet:

Although genetic material is vertically transferred between generations via sexual or asexual reproduction, similarities in some chromosome and gene parts of unrelated organisms provide important clues for another way of transfer. The mobility of genetic information among different organisms, known as horizontal gene transfer (HGT) has immediate or delayed effects on the recipient host. One of the most notable mechanisms of HGT is natural transformation (NT), a process in which cells take free DNA from the extracellular environment and incorporate it into their chromosomes by homologous recombination. NT is widely conserved in many bacterial species as it can promote to spread of resistance genes. Although it is known that many organisms rely on HGT, there is limited information about how they decide which particular genetic material to horizontally transfer. Here, I have investigated the preference priority among different gene sources presented under certain stress conditions for Bacillus subtilis possessing NT ability. To test this, two DNA specimens (E and C) with different sequence contents of the same length were presented to B. subtilis under different stress environments (BK, BC, BE and BCE). The hypothesis was evaluated according to the analysis of the results of colonial formations on selective plates (pE, pC and pCE). The obtained data presented a strong positive correlation that the bacteria have preference priority during NT depending on a stimulator. The tendency of the bacteria to uptake useful DNA fragments in a specific environment can be suggested. For instance, the majority of colonies grow on pE plates rather than the pC and pCE when the transformation media includes erythromycin (Eryt) as an inducer. Although the data significantly overlaps with the idea claiming that the bacteria have a preference priority to uptake free DNAs during NT, further investigations are needed to support the present data and for better understanding of the phenomenon.