European Journal of Molecular Biotechnology

118-130

Authors: Firas Rashad Al-Samarai, Abdulkareem A. Al-Kazaz

The dramatic development of molecular genetics has laid the groundwork for genomics. It has introduced new generations of molecular markers for use in the genetic improvement of farm animals. These markers provide more accurate genetic information and better understanding of the animal genetic resources. Scientists, unfamiliar with the different molecular techniques tend to get lost as each has its own advantages and disadvantages. This review represents a trail to shade alight on the different types of molecular markers by introducing a brief summary on the development of genetic markers including both the classical genetic markers and more advanced DNA-based molecular markers. This review could be helpful to better understand the characteristics of different genetic markers and the genetic diversity of animal genetic resources.

156-173

Authors: Oleg Mosin, Ignat Ignatov

This paper deals with studying biosynthetic pathways of 2H-labeled purine ribonucleoside inosine excreted into liquid microbial culture (LC) by Gram-positive chemoheterotrophic bacterium Bacillus subtilis B-3157 while growing of this bacterium on heavy water (HW) medium with 2% (v/v) hydrolysate of deuterated biomass of the methylotrophic bacterium Brevibacterium methylicum B-5662 as a source of 2H-labeled growth substrates. Isolation of 2H-labeled inosine from LC was performed by adsorption/desorption on activated carbon with following extraction by 0,3 M ammonium–formate buffer (pH = 8,9), crystallization in 80% (v/v) EtOH, and ion exchange chromatography (IEC) on a column with AG50WX 4 cation exchange resin equilibrated with 0,3 M ammonium–formate buffer and 0,045 M NH4Cl. The investigation of deuterium incorporation into the inosine molecule by FAB method demonstrated incorporation of 5 deuterium atoms into the molecule (the total level of deuterium enrichment – 65,5 atom% 2H) with 3 deuterium atoms being included into the ribose and 2 deuterium atoms – into the hypoxanthine residue of the molecule. Three non-exchangeable deuterium atoms were incorporated into the ribose residue owing to the preservation in this bacterium the minor pathways of de novo glucose biosynthesis in 2H2O-medium. These non-exchangeable deuterium atoms in the ribose residue were originated from HMP shunt reactions, while two other deuterium atoms at C2, C8-positions in the hypoxanthine residue were synthesized from [2H]amino acids, primarily glutamine and glycine, that originated from deuterated hydrolysate. A glycoside proton at -N9-glycosidic bond could be replaced with deuterium via the reaction of СО2 elimination at the stage of ribulose-5-monophosphate formation from 3-keto-6-phosphogluconic acid with subsequent proton (deuteron) attachment at the С1-position of ribulose-5-monophosphate. Two other protons at C2(C3) and C4 positions in ribose residue could be replaced with deuterium via further enzimatic isomerization of ribulose-5-monophosphate into ribose-5-monophosphate.