Enzyme immunassay of alternariol for the assessment of risk of agricultural products contamination

A highly specific test system based on polyclonal rabbit antibodies targeting a conjugate of alternariol and bovine serum albumin prepared by formaldehyde condensation has been developed for the first time and shown to have the sensitivity of 0.4 ng/ml in the indirect competitive determination of alternariol. The possibility of applying the assay for assessment of the intensity of alternariol contamination of corn, animal feed, and raw materials used for the preparation of the latter has been demonstrated.     

On the issue of innervation of dorsal longitudinal musculature of <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> with inferior cervical nerve

Using the method of the anterograde dextran tetramethylrhodamin transport, there is obtained the topographic picture of branching of inferior cervical nerve axons on fibers of the dorsal longitudinal muscle in Lymnaea stagnalis (L.). Using the retrograde staining, the neuronal bodies sending their processes into this nerve are marked. Manifestations of asymmetry in distribution of neurons stained through the right and left nerves are described. The electron microscopic studies have shown that the main number of the inferior cervical nerve axons is represented by thin fibers presumably belonging to the sensory cells. A part of the nerve fibers and their endings show imunoreactivity to serotonin and acetylcholine. The serotoninergic fibers predominate quantitatively over the cholinergic ones and account for a half of the fibers stained with dextran. A possible functional role of the serotoninergic and cholinergic innervation of the dorsal longitudinal muscle in Lymnaea stagnalis is discussed.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 40, No. 6, 2004, pp. 569–578.     

Enzyme immunoassay of the secondary metabolites of micromycetes as components of lichen substances

The composition of low-molecular biologically active metabolites typical of microscopic fungi has been studied in blastemas of fruticose lichens of the genera Cladonia, Cetraria, Evernia, Bryoria, and Usnes. The enzyme immunoassay method showed the presence of sterigmatocystin, emodin, mycophenolic acid, citrinin, alternariol, and diacetoxyscirpenol, which occurred regularly and, in most cases, at a frequency of 55 to 100%. The highest levels of accumulation were 0.001-0.003% for emodin, 0.0002% for alternariol and citrinin, 0.0001% for sterigmatocystin and mycophenolic acid, and 0.00005% of the weight of air-dry material for diacetoxyscirpenol. Other metabolites (cyclopiazonic acid, ergot alkaloids, ochratoxin A, PR toxin, deoxynivalenol, zearalenone, and fumonisins) were detected in these lichens less frequently (sometimes only upon the expansion of the territory of sampling), and their content was no more than 0.00005%. The peculiarities of the component composition and the levels of accumulation of fungal metabolites in lichens of different taxonomic affiliation were discussed.     

The oxidation rate of high-potential c-type cytochrome in the photochemical reaction centre is temperature-independent

The temperature dependence of laser-induced (694.3 nm, 30 ns, 10 mJ.cm-2) high-potential cytochrome c (Em=+290 mV) oxidation kinetics was studied in Ectothiorhodospira shaposhnikovii chromatophores. It was shown that the rate constant of this reaction is independent of temperature in the range of 300 K to 120 K.     

M?ssbauer spectroscopy of intramolecular mobility in chromatophores from Rhodopseudomonas spheroides

Mobility of the M?ssbauer label attached to the membrane proteins and the M?ssbauer probe embedded into the lipid matrix of the bacterial chromatophores were studied. Positive correlation was established between the dynamic properties of hydrophobic compartments in the chromatophores and functional electron--transport activity at the level of quinone cofactors associated with the photosynthetic reaction centres.     

Lactate dehydrogenase activity and its isoenzyme spectrum in the human pancreas in the prenatal period

Lactate dehydrogenase (LDH) activity and the character of its isoenzyme distribution in pancreas of the human embryos and feti of the 5th-13th-week development were studied. It is shown that LDH activity was rather high already in early periods of the embryonic development, peaks of the enzymic activity were observed after 7-8 and 12-13 weeks. The isoenzymic LDH spectrum was characterized by the presence of four isoenzymes: LDH1, LDH2, LDH3, LDH5. Isoenzyme LDH4 was absent in the human pancreas in all the studied periods of embryonic development. The data obtained evidence for intensity of the glycolysis processes at LDH reaction level in the prenatal ontogenesis period and they reflect most probably the processes of development and differentiation ox cellular populations in the given organ.     

Producers of mycophenolic acid in ensiled and grain feeds

Using the reaction of activated N-hydrooxisuccinimide ester of mycophenolic acid, a series of immunoreactive conjugated antigens with albumins, gelatin, and glucosoxidase is obtained. On the basis of polyclonal rabbit antibodies, a test-system for indirect competitive immunoenzyme analysis is elaborated, which has the sensitivity 0.4 ng/ml. By immunoanalysis, the ability for active biosynthesis of mycophenolic acid in strains of Byssochlamys nivea (44/44, 4100-68400 ng/ml) and Penicillium roqueforti (7/16, 204-25120 ng/ml) from the mycobiota of ensiled feeds is confirmed. The correspondence between weakly expressed producing capacity of most species of fungi of the genera Penicillium and Aspergillus prevailing in grain feeds and the data on low occurrence of this metabolite in grain (8.0%) and combined feeds (11.9%) is confirmed. A potential relationship between particular cases of a significant accumulation of mycophenolic acid (from 500 to 1500 μg/kg) in grains of wheat, corn, and combined feeds and a high biosynthetic activity in rare species P. puberulum, P. stoloniferum, and P. gladioli is discussed.     

Electron-conformation transitions in the complex of bacterial photosynthetic reaction centers with cytochromes

A theoretical model of conformation--regulated electron transfer from multihaem cytochrome c to bacteriochlorophyll of the reaction centre (RC) is considered. The theoretical data are compared with the experimental ones on the basis of temperature dependence of laser-induced electron transfer from high-potential cytochrome Ch bacheriochlorophyll of RC in Ectothiohodospira shaposhnikovii chromatophores. From this comparison there were calculated the thermodynamic characteristics of cytochrome Ch transfer from the configuration without electron transfer to RC bacteriochlorophyll into the coordinated configuration with an effective transfer. The values obtained are: H = 7,1 kJ/M; S = --(30,2--36,9) J/grad. M. Possible regulatory role of such conformation transitions is discussed.     

Multiplicity of chemical mechanisms of regulation of muscle contractions in <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> L.

Effects of acetylcholine, octopamine, and their antagonists, as well as of glutamic acid were studied on contractions of dorsal longitudinal muscle of the mollusc Lymnaea stagnalis L., evoked by electrical stimulation of n. cervicalis inferior. Acetylcholine and octopamine increased amplitude of contractions evoked by applications at concentrations about 10^–8 M and decreased at concentrations higher than 10^–7 M. Glutamic acid produced only inhibitory effect on the contraction amplitude, which appeared at concentrations beginning from 10^–9 M and higher. The acetylcholine antagonists atropine and d-tubocurarine also decreased amplitude of evoked contractions. Their blocking effect rose with increase of their concentrations in the range from 10^–9 M to 10^–5 M. Specificity of the effect of the studied substances was established in experiments with a combined application of the transmitters and their antagonists. The obtained results indicate multiplicity of chemical mechanisms of regulation of contractions of the dorsal longitudinal muscle in L. stagnalis.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 1, 2005, pp. 44–50.Original Russian Text Copyright © 2005 by Kononenko, Zhukov.