Colorectal cancer with its frequency, high mortality rate as well as many etiological unknowns is a challenge to contemporary science. Finally, genetic information could be used in near future for prevention of colorectal cancer, its early diagnosis and selection for the most suitable hospital treatment. In this study, we analysed genetic alterations of tumor suppressor genes and the possibility of quick and efficient screening method for identification of colorectal cancer. The study consisted of 54 samples of tumor and surrounding healthy tissue of patients with colorectal cancer, which is clasificated according to Bethesda and Amsterdams criterias. The investigation showed that genetic alterations of tumor suppressor gene NM 23 were present in 19/35 (54,29%) samples, and tumor suppressor gene p53 in 18/35 (51,43%), APC in 18/35 (51,43%), DCC2 tumor suppressor gene in 12/35 (34,29%), tumor suppressor gene RB1 in 8 /35 (22, 86%) and DCC 1 in 10/35 ( 28,57%) tumor tissue.

Somatic mutations of MMR gene are not often present in HNPCC and in sporadic RER+ colorectal cancers. Complete studies were made according to Bethesda and Amsterdam Criteria, and 35 patients belonged to the group with sporadic colorectal cancer, and 9 patients belonged to HNPCC group. The results of our studies showed that there is no significant difference between RER phenotype of HNPCC and sporadic cancer (p>0,05) in regard to microsatellite status. It can be a good indicator that there are so called 'susspected' on HNPCC among sporadic cancers which were not detected yet. The reason for this was an incomplete familial history of illness of patients and as such it was selected as sporadic cancer. Microsatellite analysis together with medical and familial history of illness can be a successful instrument for efficient HNPCC identification. However, successful solving of this problem lies in making an accurate diagnosis in comparative findings, which can be provided by genetic and clinical tests.

Phenazines, secondary metabolites of fluorescent Pseudomonas, represent a group of heterocyclic nitrogen-containing compounds showing a broad spectrum of antibiotic properties. Phenazines producing fluorescent Pseudomonas species are studied extensively for their application in plant disease management. In this study, we examined the antifungal activity of different indigenous Pseudomonas isolates (Q16, B25 and PS2) against the phytopathogenic fungus Alternaria tenuissima, which had infected cardoon (Cynara cardunculus L., Asteraceae). An in vitro experiment demonstrated the antifungal activity of selected indigenous isolates. In addition, an in vivo experiment under gnotobiotic conditions showed suppression of C. cardunculus disease caused by A. tenuissima. The quantification of phenazines revealed significant amounts of phenazine-1-carboxylic acid (PCA) and 2-hydroxy-phenazine-1-carboxylic acid (2-OH-PCA). PCR analysis confirmed the presence of PCA genes in all examined indigenous Pseudomonas isolates. Based on our results, we assume that these Pseudomonas isolates have potential in controlling plant diseases caused by A. tenuissima. [Projekat Ministarstva nauke Republike Srbije, br. III46007 and br. TR31018]