Penicillium urticae Bainier enumeration in soils

Summary A dilution plating method estimatedPenicillium urticae Bainier numbers in soil. This method, which used an agar layering technique and a cyclic incubation of 8 hours at room temperature (about 25°C) and 16 hours at 5°C, permitted the differential growth and sporulation in favor ofP. urticae B. over other common soil fungi.Procedures of extraction, paper chromatography, infrared analysis, and bioassay assayed for accumulated patulin. A combination of these methods routinely estimatedP. urticae B. numbers in soils and authenticated patulin production by selected isolates.Contribution from the Northern Plains Branch, Soil and Water Conservation Research Division, Agricultural Research Service, USDA, in cooperation with the Nebraska Agricultural Experiment Station, Lincoln. Published as Paper No. 2275, Journal Series, Nebraska Agricultural Experiment Station.Soil Scientist, USDA, Grand Junction, Colorado (formerly Chemist, USDA, Lincoln, Nebraska); and Microbiologist, USDA, Lincoln, Nebraska, respectively.     

A manganese requirement for patulin biosynthesis by cultures of Penicillium urticae

Antibiotic production by submerged cultures of Penicillium urticae required manganese supplementation of the media. Thus, manganese supplementation (152 M) allowed accumulation of patulin to high concentrations (2 mol/mL), whereas manganese deficiency (1.53 M) resulted in the accumulation to similar levels of the first committed pathway intermediate, methyl-salicylic acid, without significant patulin accumulation. Preliminary studies suggest that a similar manganese effect may occur in other fungal species.     

Patulin Production by Penicillium urticae Bainier in Batch Culture

A still, batch-culture method, with potato dextrose medium and Penicillium urticae Bainier, produced patulin yields of 1.2 to 1.7 g/liter of medium. Incubation was at 25 C for 14 days. Ethyl acetate extraction of condensed culture filtrate and drying with anhydrous MgSO₄, followed by solvent change to dry ethyl ether and purification on alumina (pH 4.5), produced pure crystalline patulin. The use of 2-liter, round-bottom flasks and a rotating vacuum evaporator provided versatile equipment and easy manipulation in the operations. Soil from wheat fields provided a convenient natural P. urticae source. Potato dextrose medium was superior to potato sucrose or Raulin-Thom media.     

Anaerobic degradation of o-phenylphenol by mixed and pure cultures

Summary An anaerobic enrichment culture that degraded 0.4 mmol/l per day of o-phenylphenol was selected from sediment of a waste water pond of a sugar factory. From the consortium an o-phenylphenol-degrading bacterium, strain B10, was isolated. Strain B10 could not degrade other aromatic substances, including phenylacetic acid, benzoate, o-hydroxybenzoate, p-hydroxybenzoate and phenol. Best growth was observed with glucose, pyruvate, lactate, methanol and H₂/CO₂ as substrates. o-Phenylphenol was slowly degraded if supplied as the only carbon source and was cometabolized in the presence of >5 mmol/l glucose. Strain B10 has not yet been assigned to a known species or family.     

The growth of Spirillum volutans ehrenberg in mixed and pure cultures

Summary The growth of Spirillum volutans in mixed culture was studied and liquid media were developed in which it grew rapidly and attained populations of over a million cells per ml. By taking advantage of their rapid and unidirectional motility, spirilla were separated from the mixed population by migration in capillary tubes. Pure cultures were achieved by growing the separated spirilla inside of dialysis sacks in contact with mixed cultures on the outside, and also by growth in an asparagine-mineral salts medium supplemented with an extract of Escherichia coli.Dedicated to Professor E. G. Pringsheim on his 80th birthday.This investigation was supported in part by grant G 9882 from the National Science Foundation.     

Anaerobic digestion of cellulose by pure and mixed bacterial cultures

Summary By enrichment technique, nine anaerobic mixed bacterial cultures were isolated, five of which showed stable cellulolysis. All cultures fermented cellulose and produced different fermentative products. Mixed culture BOC 25 yielded major levels of acetate and ethanol (39.6 and 12.0 mmol/l, respectively) and minor levels of propionate (2.5 mmol/l) and digested filter paper cellulose to the extent of 32.5% w/v. BOC 25 digested cellulosic and lignocellulosic substrates and produced filter paper cellulase, carboxymethyl cellulase, Avicelase and -glucosidase. Strain DC 25, a cellulolyticClostridium was purified from one of the mixed cultures. The fermentation products of DC 25 from cellulose, cellobiose or glucose were ethanol, acetate, formate, H₂ and CO₂.     

Anaerobic degradation of phenylacetic acid by mixed and pure cultures

Summary A phenylacetic acid-degrading mixed culture was enriched from effluent of an anaerobic reactor for the treatment of waste water from cellulose bleaching. From this consortium a phenylacetic acid-degrading pure culture, strain DSU3, was isolated and, due to its typical morphology and substrate spectrum, tentatively classified as a Desulfosarcina sp. It could grow on and degrade phenylacetic acid, cyclohexane carboxylate, cyclohexylacetate, benzoate, fumaric acid and several volatile fatty acids, while phenol, o-hydroxybenzoate, p-hydroxybenzoate and glucose were not utilized. Production of mandelic acid from phenylacetic acid by the enrichment culture and utilization of benzoate, an intermediate of the mandelic acid pathway, by strain DSU3 may presumably indicate degradation of phenylacetic acid via the mandelic acid pathway.     

Overlapping of normal and malignant mouse cells in pure and mixed cultures

Cultured malignant mouse melanoma cells and mouse ascites carcinoma cells, after 24 h incubation with normal mouse cells or with each other, had much higher homologous overlap indices than those recorded from pure cultures of each cell type. The effect was particularly evident in ascites cells. Normal cells of mice of different ages showed varying responses in overlap frequency when incubated with malignant cells. Conditioned medium from each malignant cell type invoked increased overlapping of cells of the heterologous malignant type but did not affect homologous cells. The effects of whole conditioned medium on heterologous malignant cells showed a graded reduction after dilution of the medium and also occurred after dialysis. A dialysable chemical factor or factors, produced by the cells, is postulated.     

Aerobic biodegradation of dinitrotoluenes in batch systems by pure and mixed cultures

Biodegradation characteristics of 2,4- and 2,6-dinitrotoluenes (DNTs) individually by pure strains and defined mixed cultures obtained from a mixed culture isolated from a slate packed bed bioreactor is described. Batch degradation experiments were carried out with free cells in submerged cultivations. The degradation rate and efficiency of five best individual bacterial strains, bacterial consortia comprising three and five of these strains, and the complete mixed culture were evaluated and compared. All the strains showed ability to degrade both the DNTs. All but one strain degraded both DNTs at the same rate. The degradation rate as well as the degradation efficiency by the mixed cultures was higher than that by the individual strains. The complete mixed culture showed 15-20x higher degradation rate than the individual bacterial strains.     

Biodegradation potential of oily sludge by pure and mixed bacterial cultures

The biodegradation capacity of aliphatic and aromatic hydrocarbons of petrochemical oily sludge in liquid medium by a bacterial consortium and five pure bacterial cultures was analyzed. Three bacteria isolated from petrochemical oily sludge, identified as Stenotrophomonas acidaminiphila, Bacillus megaterium and Bacillus cibi, and two bacteria isolated from a soil contaminated by petrochemical waste, identified as Pseudomonas aeruginosa and Bacillus cereus demonstrated efficiency in oily sludge degradation when cultivated during 40 days. The bacterial consortium demonstrated an excellent oily sludge degradation capacity, reducing 90.7% of the aliphatic fraction and 51.8% of the aromatic fraction, as well as biosurfactant production capacity, achieving 39.4% reduction of surface tension of the culture medium and an emulsifying activity of 55.1%. The results indicated that the bacterial consortium has potential to be applied in bioremediation of petrochemical oily sludge contaminated environments, favoring the reduction of environmental passives and increasing industrial productivity.     

Analytical differentiation of wine fermentations using pure and mixed yeast cultures

Summary Thirty-three fermentations of Pedro Ximénez grapes, collected in three degrees of ripeness, were carried out by inoculation with three types of inoculum: pure cultures ofSaccharomyces cerevisiae races and ofTorulaspora delbrueckii, indigenous yeasts, and mixed cultures of indigenous yeasts enriched with the pure cultures. By means of variance analysis 21 compounds were determined whose final concentrations in the wines significantly depended on the musts, the inocula or both. Eleven products that depended significantly on the inocula were subjected to a discriminant analysis in which most of the pure cultures gathered in a discriminant space area different from that occupied by the indigenous yeasts. The centroids corresponding to most of the mixed cultures were shifted to the central area of the discriminant space, moved away from their corresponding pure cultures and approached the indigenous yeasts. The results show a high similarity between the fermentations carried out with mixed cultures with the addedS. cerevisiae races and those fermentations carried out with the indigenous yeasts, with regard to those compounds which were significantly dependent on the inocula.     

Lethal activity of miconazole in Neisseria gonorrhoeae grown in pure and mixed cultures

Abstract Low concentrations (e.g. 2 × 10⁻⁶ M) of an imidazole derivative anti-fungal agent, miconazole, were lethal for the Gram-negative, facultative aerobic pathogen Neisseria gonorrhoeae grown either alone or in mixed culture with the yeast Candida albicans . Electron microscopic observation of Neisseria cells exposed to miconazole showed the presence of blebs in the outer wall and areas of separation between the wall and the cytoplasmic membrane. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cell lysates did not reveal differences in major outer membrane proteins between the treated and the untreated cells of any one strain. Imidazole derivatives are frequently used in the treatment of candidiasis. Our in vitro results show that low concentrations of one of them, miconazole, can be bactericidal for N. gonorrhoeae , a bacterium that can colonise sites of the human body where Candida is often found.     

Biodegradation of chlorophenols by mixed and pure cultures from a fluidized-bed reactor

An aerobic, continuous-flow fluidized-bed reactor was established with inoculum from activated sludge, and fed a mixture of 2,4,6-trichlorophenol (TCP), 2,3,4,6-tetrachlorophenol (TeCP) and pentachlorophenol (PCP) as the sole sources of carbon and energy for 2 years. Experiments with the enrichment were performed with material from the reactor. Later, degradation experiments were completed using pure cultures of bacteria that were isolated from suspended samples of the carrier biofilm. In batch-bottle bioassays, the reactor enrichment degraded PCP, TeCP and TCP both in mineral salts (MS) and tryptone-yeast extract-glucose (TGY) media. ortho-Methoxylated chlorophenols including 4,5-dichloroguaiacol (4,5-DCG), tetrachloroguaiacol (TeCG) and trichlorosyringol (TCS) resisted biodegradation by the enrichment both in MS and TGY media, whereas 5,6-dichlorovanillin (5,6-DCV) was readily transformed to an unidentified metabolite. Experiments with ¹⁴C labeled chlorophenols showed mineralization of 2,4-dichlorophenol (DCP) and 2,3,5-TCP to ¹⁴CO₂ by the enrichment. Material from the suspended biofilm after continuous chlorophenol feeding for 2 years was inoculated onto TGY-agar plates, and showed predominantly two colony, types accounting for over 99% of the total colony counts. The two colony types, were equal in abundance. Six Gram-negative, oxidase- and catalase-positive, non-fermentative small rods were isolated in TGY agar media supplemented with 10 mg/l of TeCP or PCP. All isolates formed colonies in TGY plus 150 mg/l of PCP. The isolates degraded TCP and TeCP but not PCP. In mixtures of isolated bacteria the rates of chlorophenol degradation were similar to those observed with individual isolates. Three isolates were identified as Pseudomonas saccharophila and three were an unidentified species of Pseudomonas.     

Perspectives in the modeling and optimization of PHB production by pure and mixed cultures

Poly(beta-hydroxybutyrate) or PHB is an important member of the family of polyhydroxyalkanoates with properties that make it potentially competitive with synthetic polymers. In addition, PHB is biodegradable. While the biochemistry of PHB synthesis by microorganisms is well known, improvement of large-scale productivity requires good fermentation modeling and optimization. The latter aspect is reviewed here. Current models are of two types: (i) mechanistic and (ii) cybernetic. The models may be unstructured or structured, and they have been applied to single cultures and co-cultures. However, neither class of models expresses adequately all the important features of large-scale non-ideal fermentations. Model-independent neural networks provide faithful representations of observations, but they can be difficult to design. So hybrid models, combining mechanistic, cybernetic and neural models, offer a useful compromise. All three kinds of basic models are discussed with applications and directions toward hybrid model development.     

Depth distribution of adults and immatures of twoTribolium Castaneum strains in pure and mixed cultures

1. The distribution of adults and immatures of two Tribolium castaneum strains in plexiglas towers was studied both in single-strain and in mixed cultures.
2. The adults of the + + strain tended to be, on the average, deeper in the flour than the bb adults, in pure and in mixed cultures.
3. Adult distribution was independent of sex.
4. The correlation between adult and egg distribution was usually negative, due to either adult movement in the flour, or to reduced fecundity and increased cannibalism of eggs where adults were numerous, or both.
5. Larvae, and especially pupae, of bb were more abundant in the upper sections, and + + in the lower sections, of towers, both in pure and in mixed cultures and, in particular, at the higher density.
6. In general, the distribution of the strains in the mixed cultures was very similar to the pure cultures, showing a very small effect of the interaction between the two strains, in comparison with GHENT’S results with two species. It seems that the two strains are very much alike in their ability to exploit their environment and therefore their success is the same (when pupal cannibalism is reduced) whether the biological component of the environment is composed of one or two strains.