Aqueous Nutrient Medium Research Articles

Metabolic responses of cultured cells to oxygenated perfluorocarbon.

Protoplast-derived cells of albino Petunia hybrida cv. Comanche were used as a model, nonphotosynthetic, eukaryotic plant system to study changes in (1) the rate of oxygen consumption as measured by a Clark-type oxygen microelectrode, (2) mitochondrial membrane potential (MMP) as assessed by Rhodamine 123 fluorescence, and (3) intracellular activities of superoxide dismutases (SOD, EC 1.15.1.1) and catalases (CAT, EC 1.11.1.6), following culture for up to 14 d in aqueous nutrient medium overlaying oxygen-gassed perfluorodecalin (Flutec PP5; F2 Chemicals, Preston, UK). The mean (+/- s.e.m., n = 7) rate of oxygen consumption of Petunia cells after 24 h of culture in the presence of oxygenated PFC was 14.3 +/- 1.6 mol O2 ml(-1) min(-1), compared to 9.7 +/- 0.8 micromol O2 ml(-1) min(-1) for untreated (control) cells (P < 0.05). Similarly, the culture of cells with oxygenated PFC for 24 h resulted in a significant (P < 0.05) increase of over 50% in the mean MMP, compared to the control. Culture of protoplasts with oxygenated PFC also produced significant (P < 0.05) increases in both mean SOD and CAT activities after 3-7 d of culture, the former comparable to that reported previously for protoplasts of Salpiglossis sinuata cultured with oxygenated PFC.

Metalaxyl toxicity, uptake, and distribution in several ornamental plant species.

Phytoremediation depends on the ability of plants to tolerate and assimilate contaminants. This research characterized the interaction between several ornamental plant species and the fungicidal active ingredient, metalaxyl [N-(2,6-dimethylphenyl)-N-(methoxyacetyl)alanine methyl ester]. Species evaluated included sweetflag (Acorus gramineus Sol. ex Aiton), canna (Canna hybrida L. 'Yellow King Humbert'), parrotfeather [Myriophyllum aquaticum (Vell.) Verdc.], and pickerelweed (Pontederia cordata L.). Metalaxyl tolerance levels for each species were determined by exposing plants for 7 d to solutions containing 0, 5, 10, 25, 50, 75, or 100 mg metalaxyl L-1 aqueous nutrient media. Response endpoints included fresh mass production after 7 d exposure and 7 d post-exposure and quantum efficiency using dark-adapted (Fv/Fm) and light-adapted (fluorescence yields) plants. Metalaxyl uptake and distribution within the plant was determined by growing plants in aqueous nutrient media containing 1.18 x 10(6) Bq L-1 [14C]metalaxyl (0.909 mg L-1) for 1, 3, 5, or 7 d. Plant tissues were combusted and analyzed by liquid scintillation counting. Metalaxyl had no effects on the endpoints measured, except for fresh mass production of sweetflag at the 75 and 100 mg L-1 treatment levels. However, leaf necrosis was apparent in most species after 5 d exposure to concentrations greater than 25 mg L-1. Metalaxyl removal from the spiked nutrient media ranged from 15 to 60% during the 7-d exposure period. The majority of metalaxyl removed from the solution was detected within individual plants. In nearly all cases, activity from the radiolabeled pesticide accumulated in the leaves. Uptake of metalaxyl was correlated with water uptake throughout the 7 d. These results suggest that all species examined may be good candidates for incorporation into a phytoremediation scheme for metalaxyl.

Phytotoxicity, uptake, and distribution of [14C] simazine in Canna hybrida ‘Yellow King Humbert’

AbstractPhytoremediation depends on the ability of plants to tolerate and assimilate contaminants. We have been interested in the use of common ornamental plants to ameliorate the impacts of pesticide waste on golf courses and ornamental plant nurseries. This research characterized the interaction between an ornamental, Canna hybrida ‘Yellow King Humbert,’ and the herbicide simazine. Simazine tolerance levels for C. hybrida were determined by exposing plants for 7 d to 0, 0.01, 0.03, 0.1, 0.3, 1.0, or 3.0 mg‐simazine/L aqueous nutrient media. Response endpoints included fresh mass production after 7 d of exposure and 7 d postexposure and quantum efficiency using dark‐adapted and light‐adapted plants. Simazine uptake and distribution within the plant was determined by exposing plants to 2.02 μCi [14C]simazine in nutrient media (0.242 mg/L) for 1, 3, 5, or 7 d. Plant tissues were combusted and analyzed by liquid scintillation counting. Fresh mass production was reduced 66 and 78% for plants exposed to 1.0 and 3.0 mg/L, respectively. Photosynthetic efficiency measured in dark‐adapted plants was reduced 34 and 60% at the same respective concentrations, whereas photosynthetic efficiency measured in light‐adapted plants was reduced 76 and 92%, respectively. Simazine activity in solution was reduced 80% over 7 d. By day 7, simazine (and/or an impurity) was distributed throughout the plant, but predominantly occurred in the leaves. Uptake of simazine was correlated with water uptake throughout the 7 d. These results suggest that C. hybrida may be a good candidate for incorporation into a phytoremediation scheme for simazine.

Changes in cell biochemistry in response to culture of protoplasts with oxygenated perfluorocarbon.

Superoxide dismutase (superoxide oxidoreductase; EC 1.15.1.1; SOD) was measured in enzymatically isolated protoplasts of Salpiglossis sinuata following culture in aqueous nutrient medium overlaying oxygen-gassed perfluorodecalin (Flutec PP6; BNFL Fluorochemicals, UK). SOD was extracted from harvested, lysed protoplast-derived cells after 1, 3, 7 and 14 days of culture and assayed spectrophotometrically. Protoplasts cultured with oxygenated PFC (+/- s.e.m, n = 5) showed significant increases in mean SOD activity to 4.2 +/- 0.1 U after 1 day (P < 0.05) and 9.3 +/- 0.7 U after 3 days (P < 0.01), with a fall in mean SOD after 7 days (5.1 +/- 0.9 U), similar to control. The decrease in SOD after 7 days correlated closely with a progressive fall in pO2 in the PFC phase over the same period. In contrast, control protoplasts (medium alone) or protoplasts cultured in medium overlaying non-oxygenated PFC showed no significant changes in mean SOD activity over the 14-day culture assessment period.

Odoriferous substances of the mycelial fungus Ashbya gossypii

and the extractive substances by three extractions with diethyl ether. At a yield of dry biomass of the fungus of 0.9-1.4 g/liter of culture liquid the yield of essential oil amounted to 109.1-113.2 ml/liter and that of extract to 105.4-112.7 mg/liter. The amount of odoriferous substances was determined gas-chromatographically by the method of internal standardization, their total amount being 74.9-81.6% on the mass of the essential oil and 57.6-68.3% on the mass of the extract. The main odoriferous components were identified in the extract by the GLC method (% on their sum): linalool. 0.2-0.6; citronellol, 0.3-3.0; nerol, 0.i-i.i; geraniol, 55.7-69.7; ~-phenylethanol, 25.1-38.6. In addition, it was observed that during the cultivation of the mycelial fungus 61.1-72.3% of extractive substances was secreted into the aqueous nutrient medium, 93.4-94.4% of their total being odoriferous substances. It must be mentioned that a certain variation in the indices given is due to differences in the compositions of the nutrient media. This is the first time that the capacity of this microorganism for producing odoriferous substances similar in composition to the essential oil of the mycelial fungus Eremothecium ashbyii [2] and fresh roses [4] has been detected.

Die Produktion ätherischer Öle durch Zellsuspensionen der Kamille in einem Zweiphasensystem

Cell suspensions of Matricaria chamomilla were cultured in a two phase system consisting of an aqueous nutrient medium and a nontoxic lipophilic phase (triglyceride). Especially during the first week of culture period a great number of lipophilic substances were accumulated in the triglyceride phase as was demonstrated by TLC and GC. One of these substances could be identified as alpha-Bisabolol using GC-MS-coupling. Cell growth was unimpaired by the addition of the lipophilic phase to the nutrient medium.

Zweiphasenkultur — ein Weg zur Isolierung lipophiler Substanzen aus pflanzlichen Suspensionskulturen

Summary A crown-gall cell suspension of Matricaria chamomilla was cultivated in a two-phase system consisting of an aqueous nutrient medium and a nontoxic lipophilic phase (triglyceride, liquid paraffine). The substances with a characteristic UV absorbance spectrum which accumulate in the lipophilic phase under the different conditions of the two phase system could hardly be detected in single-phase culture. The growth characteristics of the cells in two phase culture are comparable to those in aqueous medium.

The Viking Gas Exchange Experiment results from Chryse and Utopia surface samples

Immediate gas changes occurred when untreated Martian surface samples were humidified and/or wet by an aqueous nutrient medium in the Viking lander gas exchange experiment. The evolutions of N2, CO2, and Ar are mainly associated with soil surface desorption caused by water vapor, while O2 evolution is primarily associated with decomposition of superoxides inferred to be present on Mars. On recharges with fresh nutrient and test gas, only CO2 was given off, and its rate of evolution decreased with each recharge. This CO2 evolution is thought to come from the oxidation of organics present in the nutrient by gamma Fe2O3 in the surface samples. Atmospheric analyses were also performed at both sites. The mean atmospheric composition from four analyses is N2, 2.3%; O2, not greater than 0.15%; Ar, 1.5% and CO2, 96.2%.