Development of a root feeding system based on a fiber ion-exchange substrate for space plant growth chamber "Vitacycle".

Selecting a plant root nutrient delivery system is one of the key aspects of designing root modules for space plant growth chambers. This article examines a number of the nutrient delivery systems and shows the most suitable technique for providing nutrients to roots in microgravity, which to date are ion-exchange artificial soils. In addition, this article characterizes the ion composition and hydrophysical parameters of a new Russian artificial ion charged fiber substrate, BIONA-V3. The BIONA-V3 substrate is comprised of ion-exchange resin fibers. The experimental data concerning the effects of anionic and cationic components on plant biomass is presented. Preliminary experiments with BIONA-V3 showed that 1 kg of dry BIONA-V3 produces up to 2.4 kg (fresh mass) of cabbage leaf or 180 g of dry plant mass per 1 dm3 of the substrate. Therefore, the root zone volume can be as small as 120 cm3 per plant. Further optimizing the nutrient composition of the resin fibers can increase space plant growth chamber productivity.

Influence of surfactants on solubilization and fungal degradation of fluorene.

Eighteen fungal strains were tested in toxicity assays with surfactants in order to select surfactants and strains tolerant to surfactants for degradation assays. Two nonionic surfactants were used, an alkylphenol ethoxylate, Triton X-100, a sorbitan ester, Tween 80 and an anionic surfactant, sodium dodecyl sulfate. Solubilization and biodegradation tests were conducted in liquid medium batch; fluorene was quantified by HPLC. Results showed the enhancement of fluorene solubilization by the three surfactants, good tolerance of nonionic surfactants by the fungal strains and the enhancement of the biodegradation of fluorene by Doratomyces stemonitis (46-62%) and Penicillium chrysogenum (28-61%) in the presence of Tween 80 (0.324 mM) after 2 days.

Pyrene degradation by two fungi in a freshwater sediment and evaluation of fungal biomass by ergosterol content.

Mucor racemosus var. sphaerosporus and Phialophora alba were investigated for their abilities to degrade pyrene in a freshwater sediment, with or without glucose supply as nutrient or carbon source, during 90 days. The ergosterol contents in sediment were quantified to estimate fungal biomass and to assess the correlation between fungal activity and biodegradation of pyrene. Results showed that, in an heterogeneous environment, these fungi presented different abilities to degrade pyrene. P. alba increased the degree of pyrene degradation by 9%, compared to the native micro-organisms, but a supply of glucose acted as an inhibitor to pyrene disappearance. M. racemosus var. sphaerosporus was not efficient at sediment bioremediation (with or without glucose added), because it reduced the rate of pyrene degradation by the native microflora. In any case, there was no increase of ergosterol in boxes during bioremediation experiments. In our experimental conditions, ergosterol content could not be correlated to pyrene degradation.

Biodegradation of pyrene by sediment fungi.

Micromycetes were isolated from PAHS-contaminated sediment and identified. They were investigated for pyrene degradation (10 mg l-1) in liquid synthetic medium for two days. Among the 41 strains isolated, 10 highly degraded pyrene (> 2.4 mg g-1 dry weight): two Zygomycetes (Mucor racemosus, M. racemosus var. sphaerosporus), 6 Deuteromycetes (Gliocladium virens, Penicillium simplicissimum, P. janthinellum, Phialophora alba, P. hoffmannii, Trichoderma harzianum), a Dematiaceae (Scopulariopsis brumptii) and a Sphaeropsidale (Coniothyrium fuckelii). Zygomycetes appeared as one of the most efficient taxonomic groups, especially with Mucor racemosus. Penicillium crustosum was the only strain that did not degrade pyrene. Among the 10 fungi which were performant for pyrene degradation, nine were not yet reported in the literature and showed a real value for PAH remediation.

Fungal degradation of fluorene.

A selection of 30 strains of micromycetes known as good degraders of polychlorinated aromatic compounds, mostly isolated from soil and belonging to various taxonomic groups, have been investigated to degrade fluorene. Toxicity assays, first evaluated on solid media, have shown high growth inhibition at concentrations above 0.001 g l-1 only towards 23% of strains. Degradation of fluorene (0.005 g l-1) was then investigated in liquid synthetic medium for 2 days and evaluated by HPLC. Among the 30 strains tested, 12 could be considered as best degraders because of a rate of degradation at 60% or over. 3 strains of Cunninghamella genus were very efficient (mean of degradation: 96%) but different strains from Ascomycetes. Basidiomycetes and Deuteromycetes were also efficient 11 strains are not yet reported in the literature: Aspergillus terreus, Bjerkandera adusta, Ceriporiopsis subvermispora, Colletotrichum dematium, Cryphonectria parasitica, Cunninghamella blakesleeana, C. echinulata, Drechslera spicifera, Embellisia annulata, Rhizoctonia solani and Sporormiella australis. A metabolic approach with standard compounds (9-fluorenol and 9-fluorenone) indicated the presence of these monooxygenated derivatives for most of the strains.

[Influence of root module design on growth and development of plants]. / Vliianie konstruktivnykh osobennostei korneobitaemykh modulei na rost i razvitie rastenii.

Wheat crop was grown in various root modules (RM) in which nutritional solution was injected through porous membrane (2-6 microns). Seeds were laid on the surface of membrane or in pearlite covering the membrane. Root modules 1 and 3 contained ceramic porous tubes 10 mm and 22 mm in diameter, respectively. RM 2 was outfitted with a porous titanium plate, RM 4--with a porous ceramic tube (Ø 10 mm) buried in pearlite, and RM 5--with a porous titanium plate under the 2.5 cm thick layer of pearlite. The area of membrane surface per one plant was equal to 3 cm2 in RM 1 and about 17 cm2 RM 2 and 3. Pearlite volume per a plant made up about 40 cm2 in RM 4.5. The object of study was Triticum aestivum L., sp. Super Dwarf. The plants grew for 49 days under the white light of luminescent lamps at water potential (WP) = -0.4, -3.0 and -5.0 kPa. WP of pearlite equal, dry mass and anticipated productivity of the crop were much higher as compared to RM without pearlite. Significant reduction of these parameters was reflective of WP drop no matter the RM type. However, it was more expressed at -5 kPa. In RM filled with pearlite the mass and productivity of crop reduced at -5.0 kPa. Design of RM essentially altered the volumetric spread of roots. Thus, root math was formed immediately on flat porous plates, commonly below the bare tubes and both on top and on the bottom of RM with pearlite. These data can help development of RM for space greenhouses.

[Investigation of the methods of extension of useful life of nanofiltration membranes in washing water regenerating system]. / Issledovanie sposobov prodleniia sroka sluzhby nanofiltratsionnykh membran primenitel'no k sisteme regeneratsii sanitarno-gigienicheskoi vody.

Transport and selective characteristics of Russian nanofiltration membranes OPMN-K were investigated in order to find approaches to extend useful life of the membranes and, therefore, of the nanofiltration assembly and the washing water regenerating system at large. Hygienic cleansing agents as washing water ingredients pollute but not irreversibly impair the membranes. Flushing of membranes after regeneration of various model detergents was shown to recover the membrane permeability virtually up to original level.

[Specifics of sorption after purification of permeates produced by nanofiltration of washing water in pressurized modules]. / Osobennosti sorbtsionnoi doochistki permeatov, poluchennykh v rezul'tate nanofil'tratsii sanitarno-gigienicheskoi vody germozamknutogo ob"ekta.

Data on the quality of sorption afterpurification of permeates produced by nanofiltration of washing water in the ECOPSY-95 project are presented. Washing water contained essentially different detergents. Nanofiltration was performed with reeled composite membrane filters (OPMN-K). Nanofiltrated permeates were further treated with sorption techniques. The investigation confirmed the possibility get a filtrate complying with the washing water requirements. It was demonstrated that afterpurification of nanofiltered permeates by sorption improves the quality of regenerated water and also extends useful life of expandable sorption materials as compared to washing water that was not subjected to nanofiltration. Combination of nanofitration and sorption can be favorable to decrease the size of filter cartridges by 30-50%.

[The use of nanofiltration for regenerating different types of water for sanitation and hygiene obtained in a hermetically sealed cabin]. / Ispol'zovanie nanofil'tratsii dlia regenratsii razlichnykh vidov sanitarno-gigienicheskikh vod, poluchennykh v germozamknutom ob''ekte.

Presented are results of evaluating transportability and selectivity of Russian OPMN-K membrane coil nanofilters used in a chamber experiment (project EPOKSI [correction of ECOPSI]-95) to clean washing water containing different detergents. OPMN-K nanofilters were potent to extract no less than 96 to 98% of permeate with the organic selectivity reaching 80 to 90%. The detergent-dependent dynamics of capacity and selectivity and data of analyses of producible permeates and concentrates are reported.

Biodegradation of fluoranthene by soil fungi.

A selection of 39 strains of micromycetes known as good degraders of polychlorinated aromatic compounds, mostly isolated from soil and belonging to various taxonomic groups, have been investigated for fluoranthene degradation. Toxicity assays, first evaluated on solid medium MEA, have not shown any toxicity of fluoranthene (1-100 mg.L-1) towards fungi. Whereas, consumption assays on a solid synthetic medium showed a toxicity at 100 mg.L-1. The degradation of fluoranthene (10 mg.L-1) was then investigated in a liquid synthetic medium for 4 days and evaluated by HPLC. Among the 39 strains tested, 18 degraded fluoranthene at 60% or more. Zygomycetes appeared to be the most efficient group (mean degradation: 90%). Among 18 performant strains, 10 had not yet been reported in the literature: Sporormiella australis, Cryptococcus albidus, Cicinobolus cesatii, Pestalotia palmarum, beauveria alba, Aspergillus terreus. Cunninghamella blakesleeana, C. echinulata, Mortierella ramanniana and Rhizopus arrhizus. Fluoranthene adsorption on fungi was very low for the strains which degraded well fluoranthene (mean adsorption: 4%). Whereas, some strains adsorbed it much more such as Colletotrichum dematium (47%) and Penicillium italicum (43%).

Biodegradation of anthracene by soil fungi. Groupe pour l'Etude du Devenir des Xénobiotiques dans l'Environnement (GEDEXE).

A selection of 39 strains of micromycetes known as good degraders of polychlorinated aromatic compounds, mostly isolated from soil and belonging to various taxonomic groups, have been investigated for anthracene degradation. Toxicity and consumption assays, first evaluated on solid media, have not shown any toxicity of anthracene (1-100 mg.L-1) towards fungi. Degradation of anthracene (10 mg.L-1) was then investigated in a liquid synthetic medium for 4 days and evaluated by HPLC. Among the 39 strains tested, 19 degraded anthracene at 50% or more. Zygomycetes appeared to be the most efficient group (mean degradation : 81%) while Melanconiales were the least efficient (mean: 14%). Among 19 efficient strains, 8 had not yet been reported in the literature: Cryphonectria parasitica, Ceriporiopsis subvermispora, Oxysporus sp., Cladosporium herbarum, Drechslera spicifera, Verticillium lecanii, Fusarium moniliforme var. subglutinans and Rhizopus arrhizus.

[Characteristics of several artificial substitutes of soil for space flight greenhouses]. / Kharakteristiki nekotorykh iskusstvennykh zamenitelei pochvy dlia kosmicheskikh oranzherei tipa "Svet".

The analysis of the study associated with cultivating the leaf cabbage, small radish in the Russian-Bulgarian greenhouse "Svet" aboard Mir orbital space station in 1990 has demonstrated that under microgravity conditions the zeolite substrate "Balkanin" with particles dimensions of 1-3 mm placed in the root modules of the greenhouse "Svet" did not ensure the sufficient transfer of the water from moisture-saturated wicks to the periphery of the vegetation vessels what is attributable to the peculiarities of hydrophysical characteristics of the substrate used. There presented the results of experimental research on the hydrophysical and agrochemical characteristics of the ion-exchange substrates of two other types--"Biona 312" and "Biona V" prepared on the basis of the artificial ion-exchange resins: cationite--CU-2 and anionite EDE-10P. For these substrates there found the estimates of humidity correlating with the loss of gassy pores as well as there measured the specific weight of the solid phase and the volumetric weight. There presented data on the content of the nutrients as well as the results of assessing the biological productivity potential of the tested substrates in the "Svet" greenhouse root modules. The characteristics obtained are indicative of the possibility to use the mentioned substrates in space greenhouse of the "Svet" type.

[Nanofiltration as a prospective method of regenerating potable and hygiene water]. / Nanofil'tratsiia kak perspektivnyi metod regeneratsii sanitarno-gigienicheskoi vody.

This work was aimed at studying the transport and selective characteristics of nanofiltration membrane of the OPMN-K type with respect to solutions contained catamine AB and amine oxide for development of promising systems of water regeneration as well as at evaluating the effect of the concentrations of solutions and working pressure of the regeneration unit on these characteristics. It is found that the selectivity of membrane with respect to the solutions contained the single constituents (catamine AB or amine oxide) considerably differed from the selectivity of membrane with respect to solution containing the mixture of catamine AB and amine oxide. Studies of this membrane give the satisfactory results in transport and selective characteristics of all tested solutions excluding the solution containing catamine AB with low concentrations. The obtained results indicate that nanofiltration may be considered as a perspective step of reclamation of sanitary-hygienic water in space flight environments.

Detoxification of ochratoxin A, a food contaminant: Prevention of growth of Aspergillus ochraceus and its production of ochratoxin A.

The toxicity of ochratoxin A (OTA), a mycotoxin produced by fungi ofAspergillus orPenicillium genera is now well documented. Its nephrotoxicity, immunosuppression, teratogenicity, and carcinogenicity have been widely studied. Physical and biochemical methods have been studied to prevent these toxinogenicAspergillus andPenicillium from producing OTA, and/or to destroy the mycotoxin when already produced in a liquid or a solid medium. Repeated freezing at - 20†C and thawing at + 26†C aleatory reduce OTA production in a liquid medium. Exposure to UV B for different periods of time is efficient in preventing OTA production in a liquid medium. Gamma-irradiation from 2 to 5 kGy gives good results in preventing the production of OTA or destroying it when already produced. Carboxypeptidase is very efficient at 5 units/50 ml in a liquid medium for cleaving the OTA already produced.

6-Allyl-5,6-dihydro-5-hydroxypyran-2-one, a lactone produced by a new Drechslera species: specified 1H and 13C NMR assignments, mutagenic and immunomodulating testings.

A lactone (6-allyl-5,6-dihydro-5-hydroxypyran-2-one) was isolated from a new Drechslera sp. 1H and 13C NMR assignments, not previously specified, are published. No mutagenic activity on Ames/Salmonella test (strains TA98 and TA100 has been observed. Results on the respiratory metabolism of J774.1 murine macrophage indicate that the lactone might exhibit immunomodulating activity as a function of time of cellular contact and of concentration.

Antitumoral activity of patulin and patulin-cysteine adducts.

A comparison between the cytotoxicity and the anti-tumoral activity of patulin and patulin-cysteine adducts has been conducted. In vitro assays using L 1210 and P 388 cells showed that patulin-cysteine adducts had less cytotoxic activity than patulin (IC50 was 4 fold of IC50 patulin). In vivo, cysteine not only reduced the toxicity of patulin but also reduced its antitumoral activity against L 1210 and P 388 mouse leukemias (respectively of 25.7% and 46.6% with 3 mg.kg-1.d-1). By addition on patulin at the 4 or 7 position, cysteine might interfere with the lactone function and the -CH2- in in position 6 which are responsible for the antitumoral activity.

Diversity in phenol-metabolizing capability of 809 strains of micromycetes.

The property of 809 strains of micromycetes to grow in the presence of phenol (0.5 g/l) was investigated on solid media. Toxicity was determined on malt extract agar medium. Growth of the fungal strains on synthetic solid medium with phenol as the sole carbon source allowed evaluation of phenol consumption. Only 61 strains (8% of the whole) grew well under both conditions, which reflects the toxicity of 0.5 g/l of phenol upon micromycetes. Finally, Phanerochaete chrysosporium was chosen and cultivated in liquid synthetic medium at 24 degrees C and 37 degrees C with phenol (0.5 g/l). It consumed phenol fast and efficiently. Growth temperature was a key parameter. Catechol, cis-cis-muconic acid and beta-keto-adipate were characterized and quantified.

Mutagenicity of substituted anthraquinones in the Ames/Salmonella microsome system.

Unsubstituted anthraquinone, 4 substituted anthraquinones (emodin, danthron, physcion, a new compound M-108-C) and 3 dimers (skyrin, rugulosin, rugulin) were tested using the Ames/Salmonella assay (strains TA98, TA100, TA1537 and TA102). Danthron and emodin were found to be mutagenic for TA1537 with or without metabolic activation, physcion only with metabolic activation. A significant difference was found between the mutagenic activities of emodin (16.2 His+/nmole) and danthron (6.5 His+/nmole) as well as a high specific mutagenic activity for physcion (11.6 His+/nmole). These results on structure-mutagenic activity relationships suggest that the 6-methyl group plays an important role in the mutagenic activity after metabolic activation. Furthermore, and contrary to emodin, physcion exhibited a weak mutagenic activity for TA102, probably due to the formation of a different metabolite. Such information is necessary to evaluate the potential carcinogenic hazard of these compounds.

Antitumor activity of patulin and structural analogs.

A comparison between the cytotoxicity and the antitumor activity of patulin and five structural analogs (isopatulin, dehydroisopatulin, dimethylisopatulin, trimethylisopatulin and isopropylisopatulin) has been established. In vitro assays using L 1210 and P 388 cells showed that the structure of the pyranic ring as well as the nature of the substituents influenced the observed activities. Among the five structural analogs of patulin assayed in vivo against Ehrlich carcinoma, L 1210 and P 388 leukemias, dehydroisopatulin was the only one to be active on all 3 types of tumors at a dose of 100 mg.kg-1.d-1. The ratio between the LD50 in mice and the active dose was 5 while with patulin it was 10. It can be assumed that the lactone function is not solely responsible for the activity of patulin and its structural analogs.

Immunotoxicity testing of mycotoxins T-2 and patulin on Balb/c mice.

The effects of patulin and T-2 toxin were investigated on immunological responses of Balb/c mice. In vitro patulin had a stimulatory effect on splenocytes at lower concentration (1 nM to 10 nM) and strongly inhibited lymphocyte proliferation at higher concentrations (ID50 from 0.02 to 0.24 microM depending on mitogens). In the same experiments T-2 toxin was 100-fold more potent (ID50 from 0.7 to 2 nM). In vivo studies on immunity were performed in mice receiving Bordetella pertussis antigens and keyhole limpet haemocyanin. Patulin significantly reduced delayed type hypersensitivity to B. pertussis antigen and did not reduce anti-KLH antibody production. T-2 toxin had no effect on delayed type hypersensitivity and reduced anti-KLH antibody production. Splenocytes were harvested in mice with or without antigen stimulation to assess mitogenic responses. Patulin generally increased splenocyte proliferation, therefore T-2 toxin effect depended on the immunological status of mice and on the dose injected. At the lower doses (0.8 mg/kg), T-2 toxin enhanced responses to mitogen, but at the greater dose (1.6 mg/kg) T-2 toxin enhanced responses to mitogen of antigen stimulated mice and decreased responses of unstimulated mice.