Secreted reporter proteins provide monitoring of intracellular events in real time without cell destruction. To create human melanoma cell lines that enables noninvasive bioluminescent monitoring of metabolic activity, a comparison of the efficiency of isoforms and mutant variants of luciferase from the Metridia longa as secreted reporter proteins in the cells of human melanoma lines Mel IL was conducted. The MLM3 deletion mutant had the highest activity in the medium of two studied isoforms and two deletion mutants of secreted M. longa luciferase during the Mel IL melanoma cell transfection. It was established that optimization of the gene structure of the selected MLM3 variant for expression in human cells increases the level of bioluminescent activity in the Mel IL cells by almost an order of magnitude. A stable Mel IL melanoma cell line with constitutive expression of the humanized hMLM3 reporter gene was obtained and characterized. The linear range of identification of living cells by the hMLM3 reporter activity was more than three orders of magnitude with a sensitivity of detection of 10 cells.
A reusable system including urease covalently bound to the surface of modified nanodiamonds (MNDs) has been developed for the multiple determination of urea. The immobilized enzyme exhibits functional activity and catalyzes the hydrolysis of urea to yield ammonia. The presence of ammonia is confirmed by the formation of a colored product after the addition of chemical reagents. It was shown that the MNDs-urease complex can function in a wide range of temperatures and pH as well as in deionized water. The complex provides a linear yield of the product at low analyte concentrations and allows the multiple determination of urea in vitro.
Biodegradability patterns of two PHAs: a polymer of 3-hydroxybutyric acid (3-PHB) and a copolymer of 3-hydroxybutyric and 3-hydroxyvaleric acids (3-PHB/3-PHV) containing 11mol% of hydroxyvalerate, were studied in the tropical marine environment, in the South China Sea (Nha Trang, Vietnam). No significant differences have been observed between degradation rates of 3-PHB and 3-PHB/3-PHV specimens; it has been found that under study conditions, biodegradation is rather influenced by the shape of the polymer item and the preparation technique than by the chemical composition of the polymer. Biodegradation rates of polymer films in seawater have been found to be higher than those of compacted pellets. As 3-PHB and 3-PHB/3-PHV are degraded and the specimens lose their mass, molecular weight of both polymers is decreased, i.e. polymer chains get destroyed. The polydispersity index of the PHAs grows significantly. However, the degree of crystallinity of both PHAs remains unchanged, i.e. the amorphous phase and the crystalline one are equally disintegrated. PHA-degrading microorganisms were isolated using the clear-zone technique, by inoculating the isolates onto mineral agar that contained PHA as sole carbon source. Based on the 16S rRNA analysis, the PHA-degrading strains were identified as Enterobacter sp. (four strains), Bacillus sp. and Gracilibacillus sp.
The results of the development and utilization of an affine magnetic sorbent with Ni 2+ ions immobilized on coal ash microspheres are reported. The applicability of the material in the isolation of Histag proteins is demonstrated by examples of the recombinant green fluorescent protein from Clytia gregaria and the Ca 2+ regulated photoprotein obelin from Obelia longissima . The specific sorption capacity of the sorbent was 2–7 mg/cm 3 for medium-size proteins (20–30 kDa). The particles are suitable for chromatography with the presence of chaotropic agents and EDTA. They are easy to manipulate as isolation of a target protein takes 30–35 min. On the one hand, the elevated affinity of the sorbent to proteins rich in native histidines may result in a high degree of irreversible sorption; on the other hand, it allows isolation of such proteins without the introduction of artificial polyhistidine fragments.
The paper addresses the possibility of controlling the microbial community composition through metabolites produced by microbes. The comparative analysis of experimental data has shown that volatile metabolites make a much greater contribution to the microbial interactions than nonvolatile ones. It has been found that interaction of microorganisms via the volatiles they release occurs frequently and is typical of a number of microorganisms. Volatile metabolites released by microorganisms produce an inhibitory, sometimes bactericidal, effect on the vital functions of bacteria. The stimulating action occurs 6–8 times less frequently. The range of action on the growth of the test cultures and the range of sensitivity to the effect of volatile metabolites of the study microbes have been found to be individual. Comparative cluster analysis of the ranges of action of 100 study cultures has shown that in the investigated set of microorganism species interaction was performed via a set of volatiles of an inhibiting action (82) and of a stimulating action (52). It has been found that release of volatile metabolites by the studied microorganisms depends upon the culture age, concentrations of components of the nutrient medium, and volatile by-products released by other microorganisms. This production can be increased or decreased by the action of volatile metabolites of other microbes. This is related to strain features and culture age. The prospects of using these regulating metabolites depend on the “range”, specificity and safety for other members of the microbial community in insufficient concentrations. Volatiles produced by plants and microorganisms as well as by other components of the system – humans and processing equipment installed inside the closed ecosystem – could influence the formation not only of the microbial community but also of the gas composition of the system’s atmosphere, through which they could affect the state of the plants. Specially performed experiments have shown that volatile metabolites of microorganisms can accumulate in their habitat, dissolve in the atmospheric water, and maintain their biological activity for days. It has been determined that volatile metabolites of some microorganisms are toxic for plants. Growth of seedling roots is inhibited more than growth of stems.
The effect of elevated temperatures of 35 and 45°C (at the intensities of photosynthetically active radiation 322, 690 and 1104 μmol·m−2·s−1) on the photosynthesis, respiration, and qualitative and quantitative composition of the volatiles emitted by wheat (Triticum aestuvi L., cultivar 232) crops was investigated in growth chambers. Identification and quantification of more than 20 volatile compounds (terpenoids-α-pinene, Δ3 carene, limonene, benzene, α-and trans-caryophyllene, α- and γ-terpinene, their derivatives, aromatic hydrocarbons, etc.) were conducted by gas chromatograph/mass spectrometry. Under light intensity of 1104 μmol·m−2·s−1 heat resistance of photosynthesis and respiration increased at 35°C and decreased at 45°C. The action of elevated temperatures brought about variations in the rate and direction of the synthesis of volatile metabolites. The emission of volatile compounds was the greatest under a reduced irradiation of 322 μmol·m−2·s−1 and the smallest under 1104 μmol·m−2·s−1, at 35°C. During the repair period, the contents and proportions of volatile compounds were different from their initial values, too. The degree of disruption and the following recovery of the functional state depended on the light intensity during the exposure to elevated temperatures. The investigation of the atmosphere of the growth chamber without plants has revaled the substances that were definitely technogenic in origin: tetramethylurea, dimethylsulfide, dibutylsulfide, dibutylphthalate, and a number of components of furan and silane nature.
For its more than thirty year long history, the experimental creation of closed ecological systems has from its very sources been distinctly and strongly motivated by the development of human life-support systems for space. As the trend developed its fundamental significance and broad opportunities of terrestrial applications of the technologies under development were coming to the foreground. Nowadays, it can be argued that development of closed ecosystems is experimental foundation of a new branch of ecology biospherics, the goal of which is to comprehend the regularities of existence of the biosphere as a unique in the Universe (in that part of it that we know, at least) closed ecosystem. Closed technologies can be implemented in life-support systems under adverse conditions of life on the Earth - in Arctic and Antarctic latitudes, deserts, high mountains or deep in the ocean, as well as under the conditions of polluted water and air. In space where the environment is hostile for life all around the cell of life should be sealed and the life-support system as close to the ideally closed cyclic turnover of the matter as possible. Under terrestrial conditions designers should strive for maximum closure of the limiting factor: water - in deserts, oxygen - in high mountains, energy - in polar latitudes, etc. Essential closure of a life-support systems withstands also pollution of the environment by the wastes of human vital activity. This is of particular importance for the quarantine of visited planets, and on the Earth under the conditions of deficient heat in high latitudes and water in and areas. The report describes experimental ecosystem 'BIOS' and exohabitats being designed on its basis, which are adapted to various conditions, described capacities of the Center for Closed Ecosystems in Drasnoyarsk for international collaboration in research and education in this field.
We describe the experimental system having maximal possible closure of material recycling in an ecosystem, including people and plants, which was carried out in a hermetically sealed experimental complex "BIOS-3", 315 m2 in volume. The system included 2 experimentators and 3 phytotrons with plants (total sowing area of 63 m2). Plants were grown with round-the-clock lamp irradiation with 130 Wm-2 PAR intensity. The plants production was food for people. Water exchange of ecosystem, as wall as gas exchange, was fully closed excluding liquids and gas samples taken for chemical analysis outside the system. The total closure of material turnover constituted 91%. Health state of the crew was estimated before, during and after the experiment. A 5-months period did not affect their health. The experiments carried out prove that the closed ecosystem of "man-plants" is a prototype of a life-support system for long-term space expeditions.