Biosynthesis and use of coproporphyrins and uroporphyrins and their metal complexes in immune analysis and diagnostic methods]

Methods of synthesis of coproporphyrin and uroporphyrin by using bacteria of the genus Arthrobacter are proposed. Metal complexes of coproporphyrin and uroporphyrin with Pt, Pd, and Zn were synthesized. Their structures were identified by spectrophotometry, IR spectrometry, 1H-NMR, mass spectrometry, and HPLC. Data showing the possibility to use coproporphyrin III-metal complexes as luminophores for fluorescence detection of tumors. The current and prospective uses of metal complexes of water-soluble natural porphyrins in advanced immunofluorescence assays are discussed.     

Microquantitative determination of glucose in solutions using microorganisms as the test system

A technique for determining small quantities of glucose in solutions and biological liquids is proposed. The assay can be performed in the presence of some other carbohydrates, except those which are transported into E. coli cells by means of the phosphoenol-transferase system. The method is based on pH-metric regictration of H+-ions which are released from bacteria as a result of glucose consumption. The suspension of cells of E coli st. M-17 was used as a test system. We can also recommend a commercial preparation of colibacterin, which contains lyophilized bacteria E. coli st. M-17 in the sucrose-gelatin medium. The sensitivity of the method is about 1 microgram of glucose in 5-10 microliter.     

Analysis of plastid DNA-like sequences within the nuclear genomes of higher plants

A wide-ranging examination of plastid (pt)DNA sequence homologies within higher plant nuclear genomes (promiscuous DNA) was undertaken. Digestion with methylation-sensitive restriction enzymes and Southern analysis was used to distinguish plastid and nuclear DNA in order to assess the extent of variability of promiscuous sequences within and between plant species. Some species, such as Gossypium hirsutum (cotton), Nicotiana tabacum (tobacco), and Chenopodium quinoa, showed homogenity of these sequences, while intraspecific sequence variation was observed among different cultivars of Pisum sativum (pea), Hordeum vulgare (barley), and Triticum aestivum (wheat). Hypervariability of plastid sequence homologies was identified in the nuclear genomes of Spinacea oleracea (spinach) and Beta vulgaris (beet), in which individual plants were shown to possess a unique spectrum of nuclear sequences with ptDNA homology. This hypervariability apparently extended to somatic variation in B. vulgaris. No sequences with ptDNA homology were identified by this method in the nuclear genome of Arabidopsis thaliana.      

Incidence and levels of fumonisin contamination in Colombian corn and corn products

A survey was conducted to determine the levels of fumonisins B1 and B2 in corn and corn-based products available in Colombia for human and animal consumption. A total of 120 samples were analyzed by acetonitrile-water extraction, cleanup with a strong-anion-exchange column, and liquid chromatography with o-phthaldialdehyde-2-mercaptoethanol derivatization and fluorescence detection. The samples of corn and corn-based products for animal intake were taken at different feed manufacturing plants, whereas the samples used for human foods where purchased from local retail stores. The number of positive samples for fumonisin B1 was 20.0% higher in corn and corn-based products for animal intake (75.0%) than in corn and corn-based products for human consumption (55.0%). The levels of fumonisin B1 were also higher in corn and corn-based products for animal intake (mean = 694 μg/kg; range = 32–2964 μg/kg), than in corn and corn-based products for human intake (mean = 218 μg/kg; range = 24–2170 μg/ kg). The incidence and levels of fumonisin B2 were lower than those for fumonisin B1. Corn and corn-based products for animal consumption had an incidence of fumonisin B2 of 58.3%, with a mean value of 283 μg/kg, and a range of 44–987 μg/kg. The incidence of fumonisin B2 in corn-based products for human intake was 35.0%, with a mean value of 118 μg/kg and a range of 21–833 μg/kg. The highest incidence and levels of fumonisins were found in samples of hominy feed, with concentrations ranging from 86 to 2964 μg/kg fumonisin B1 and 57 to 987 μg/kg fumonisin B2.     

Prophage CTXphi genome variability and its role in alteration of Vibrio cholerae El Tor virulence characteristics

Comparative analysis of CTXphi prophage genome of 366 V. cholerae El Tor strains isolated from infected people and water was carried out using the polymerase chain reaction. Four groups of vibrios, which carry different combinations of ctxA, zot, and ace genes from core region of CTXphi prophage coding key (cholera enterotoxin) and accessory (Zot and Ace toxins) pathogenicity factors, were determined: ctxA(+) zot(-) ace(+), ctxA(-) zot(+) ace(+), ctxA(-) zot(+) ace(-), ctxA(-) zot(-) ace(+). Vibrios that had lost all tested genes were also revealed. Genomic rearrangements occurring in water environment in virulent V. cholerae strains, which acquired foreign pathogenicity genes necessary for their existence in human organism, were proposed as one of the mechanisms of formation of clones with an incomplete or no prophage. Infection process in model animals challenged with wild and isogenic strains of V. cholerae differing in the set of the phage genes (ctxA, zot, and ace) was comparatively analyzed. It was shown that variability of CTXphi prophage genome was an important factor of modification of cholera vibrios virulent characteristics. Obtained data point to usefulness of ctxA, zot, and ace phage genes detection in wild V. cholerae isolates as it could permit evaluation of their virulent potential determining the severity of the infection.     

Coproporphyrins,Uroporphyrins, and Their Metal Comlexes: Biosynthesis and Application to Immune Analysis and Diagnostic Methods

Methods of synthesis of coproporphyrin and uroporphyrin by using bacteria of the genus Arthrobacterare proposed. Metal complexes of coproporphyrin and uroporphyrin with Pt, Pd, and Zn were synthesized. Their structures were identified by spectrophotometry, IR spectrometry, ¹H-NMR, mass spectrometry, and HPLC. Data showing the possibility of using coproporphyrin III–metal complexes as luminophores for fluorescence detection of tumors was gathered. The current and prospective uses of metal complexes of water-soluble natural porphyrins in advanced immunofluorescence assays are discussed.