Porphyromonas gingivalis has been implicated as a major pathogen in adult periodontitis that has an essential growth requirement for iron, preferably in the form of haem or haemin. The virulence of I? gingivalis is dependent on its ability to acquire haem. A search of the TIGR l? gingivalis database revealed two putative haemhron ABC transport systems in I? gingivalis: the htr (haemin transport) and fet (Fe transport) loci. Thefet locus is proposed to consist of a TonB-linked outer membrane receptor (fetA), a ferrochelatase (fetB), a periplasmic binding protein (fetC), a permease (fetD) and an ATP-binding protein (fetE). We have shown that FetB it is a peripheral outer membrane protein involved in haemin binding and have proposed a function for iron removal at the surface of l? gingivalis. The htr locus is proposed to consist of genes encoding a putative periplasmic binding protein (htrA), a permease (htrB), an ATP-binding protein (htrC), a protein of unknown function (htrD) and a TonB-linked outer membrane receptor (tlr). Our results show that htrA-D are co-transcribed as an operon whereas tlr, located immediately downstream from htrD is transcribed as a separate mRNA transcript. We have insertionally inactivated htrA in I? gingivalis YH522 and shown that the I! gingivalis YH522IhtrA-strain grows poorly in low levels of haem in comparison to YH522. Kazakhstan, Almaty The caryotypes of the males of 0.a. collium (Karaganda region), 0.a. rarelini (Central Tien-Shan), 0.a. littledalei (Dzhungarian Ala-Tau, mauntains) and argali population from Chu-Ili mountains have 2n=56. The autosomes are consist from 2 pairs of metacentric and 25 pairs of acrocentric chromosomes. X is large acrocentric, Y is the least chromosome. The 20 arbitrary primers and their pairs, as the genetic markers of argali populations were tested by the PCR-R4PD method. All argali forms, excluding 0.a. collium had the similar patterns od PCR-R4PD products. The results indicate that the argali from Dzhungarian Ala-Tau and Chu-Ili mountains are similar with 0.a. rarelini. 562 Computer-based prediction of exogenous gene clusters and genome H. Stmad, P. Ulbrich, J. Paces, V.