Xenobiotic biotransformation potential of Pseudomonas rhodesiae KCM-R5 and Bacillus subtilis KCM-RG5, tolerant to heavy metals and phenol derivatives

Two environmental bacterial isolates KCM-R5 and KCM-RG5 were selected from xenobiotic-polluted environment. KCM-R5 was identified as Pseudomonas rhodesiae and KCM-RG5 as Bacillus subtilis. KCM-R5 demonstrated tolerance to heavy metals and KCM-RG5 to heavy metals and phenol derivatives. Both strains were studied for xenobiotic biotransformation in order to contribute towards bioremediation of polluted environments. Pseudomonas rhodesiae KCM-R5 and Bacillus subtilis. KCM-RG5 possess unusual ability to utilize ortho-nitrophenol (o-NP) and 2,4- dichlorophenoxyacetic acid (2,4-D). o-NP and 2,4-D were added at concentration 30 mg/l. The possible indictive/inhibiting effect of Pb cations (40mg/l) was also studied. Pseudomonas rhodesiae KCM-R5 removed 86 % of o-NP and below 1% of 2,4-D. Bacillus subtilis KCM-RG5 eliminated 83% of o-NP andunder 1% of 2,4-D. Biotransformation effectiveness of o-NP reached 95-100% in contrast to 2,4-D where the effectiveness was just 15-20%. Cell morphological changes were registered during the biotransformation processes. The obtained results could contribute to manage bioremediation processes in polluted with heavy metals and phenol derivatives environments. . 1, . 2, . 2, .

Microbial diversity in heavy-metal polluted waters

Indigenious water microflora as well as the presence of metal- and xenobiotic biotransforming bacteria were investigated in waters near the KCM Pb-Zn smelter, South Bulgaria. Content of As, Hg, Cd, Mn, Pb, Cu and Zn exceeded in times the maximum permission standart. Absence of some microbial groups demonstrated a change in the microbial community structure in the region. Ecotoxicology test ISO/DIS 10712.2 displayed toxic environmental effect of the polluted waters, especially one of them which demonstrated 72 % of ecotoxicity. More than 20 ecologically relevant new bacteria were cultured. Three of them demonstrated tolerance to Cd, Cu and Mn and five- a tolerance to 2,4-dichlorphenoxyacetic acid. Our result revealed that the heavy metal pollutions reduced the microbial diversity in the studied waters, are ecotoxic as well as that some of newly isolated bacteria possess a capacity for a clean-up biotechnologies in the region. . 1, . 2, 2., 3, 3, .

Phenol Biodegradation by Two Xenobiotics-Tolerant Bacteria Immobilized in Polyethylene Oxide Cryogels

Biofilms were formed on poly(ethylene oxide) (PEO) cryogels by using bacteria cultured from xenobiotics polluted environments and their phenol biodegrading capability was studied. PEO cryogels were synthesized via UV irradiation cross linking of moderately frozen aqueous system. Two xenobiotics tolerant bacterial isolates KCM R5 and KCM RG5 were used to construct the biofilms on the cryogels. Obtained PEO-biofilms were assessed for their ability to remove phenol at concentrations 300, 400, 600 and 1000 mg L-1 for 28 days. The biofilm PEO-KCM RG5 removed phenol up to 600mg L-1/24 h, whereas the biofilm PEO-KCM R5 was able to degrade up to 1000 mg L-1/24 h. The high content of free-water in the cryogels allowed reproduction of the used bacteria. The high content of free-water in the cryogels allowed reproduction of the used bacteria. Short initial adaptation of the PEO-bio�lms with 100 mg L-1/24 h phenol was crucial for protecting the bacterial cells from dead. The obtained results showed that the liquid debit through the bio�lms on the 28th day of the experiments was lower than at the beginning. The cryogels demonstrated non-toxicity, high biocompatibility with bacteria and excellent mechanical characteristics. After aggressive phenol treatment the PEO-biofilms remained compact, porous and elastic. The investigated new biological materials demonstrate potential for application in the industrial wastewater treatment technologies

Culture-Dependent Approach for Determining Microbial Diversity in Soils from KCM/AGRIA Region

Significant shifting of the microbial communities structure was detected in three metal-polluted soils collected around the Pb-Zn smelter KCM and the agrochemicals factory AGRIA, situated near the town of Plovdiv, Bulgaria. Industrial-, dumpsite- and agricultural soils were contaminated with As: 7.5-52.9 mg/kg; Hg: 0.086-0.404 mg/kg; Cd: 2.3-71.1 mg/kg; Mn: 742-1510 mg/kg; Pb: 138-2560 mg/kg; Cu: 32-268 mg/kg and Zn: 293-4490 mg/kg. Remarcable ecological disturbance was found in the agricultural soil using ecotoxicological test with type strain Pseudomonas putida DSM 50026 (ISO 10712). In order to assess ecologically relevant bacteria over twenty soil bacterial isolates were cultured. Six of them possess tolerance to one or more heavy metals. Four of the isolates demonstrated herbicide tolerance to 2,4-dichlorphenoxiacetic acid. Our results suggest that the microbial community responds to long-term metal- and pesticides contamination through changes in microbial community structure and selection for resistance. *** and.

The study of the apoptogenic effect of pyrimidine derivatives on murine leukemia cells

BACKGROUND: In the light of the recent findings concerning the role of apoptosis and of tumor cell enzymes in cancer chemotherapy, the interest in pyrimidine derivatives has greatly increased. Thio- and hydrazine- pyrimidines were synthesized as potential antimetabolites inhibiting the biosynthesis of nucleic acids. Some of them demonstrated biological activity, including antibacterial and antitumor action. The aim of this study was to analyze the cytotoxic activity and the ability of some derivatives to induce apoptosis in murine leukemia cells. METHODS: Exponentially growing cells were incubated with compounds and after 24, 48, and 72 hours were stained with trypan blue and counted hemocytometrically. For detection of the cell fraction undergoing apoptosis, a morphological analysis was made using fluorescent dye propidium iodide. RESULTS: Eight thio- and hydrazine- pyrimidine derivatives were investigated. 2-Thiouracil and 6- hydrazinouracil did not influence the cell growth. 2,4-dithiouracil, 2-thio-4-hydrazinouracil, 2-hydrazinouracil, and 2-thio-5-fluorouracil decreased cell proliferation, but even at the highest studied concentration (1000 µM) had no cytostatic action. Only high concentrations of 2,4-dihydrazinouracil and 2- chloro-4-hydrazinouracil showed a strong cytotoxic activity. The treatment with 2,4-dihydrazinouracil as well as with 5-fluorouracil caused the appearance of apoptotic cells with typical fragmented condensed nuclei, ghosts and apoptotic bodies. In contrast, dead cells treated with 2-chloro-4-hydrazinouracil did not show apoptotic morphology. CONCLUSION: Among studied eight thio- and hydrazine- pyrimidine derivatives only 2,4-dihydrazinouracil demonstrated strong apoptogenic activity. Its active concentrations were about 100 times higher than apoptogenic concentrations of 5-fluorouracil which points to different mechanisms of cytotoxic action

Montenegro

The study of the apoptogenic effect of pyrimidine derivatives on murine leukemia cell

In vitro assessment of the cytotoxic effects of novel RGD analogues

The RGD sequence is present in many extracellular matrix proteins and intracellular proteins, including caspases. Synthetic RGD peptides may affect adhesion, migration and tumour metastasis, or directly induce apoptosis. Several RGD peptides were synthesized, and their anti-adhesive and cytotoxic properties were analyzed in vitro. Here we present the cytotoxic activities of RGD, R(NO2)GD, CavGD and RGD-OMe on non-tumour 3T3 cells and tumour cell lines HepG2 and MCF-7. The cell growth inhibitory effects of RGD-OMe are significantly higher than those of RGD on the cell lines used. Evidently the modification in the carboxylic group of RGD with simple esterification increases the cell growth inhibitory effects of the parent compound