Squamocin, an annonaceous acetogenin, enhances naphthalene degradation mediated by Bacillus atrophaeus CN4 / Squamocin, una acetogenina annonácea, estimula la degradación de naftaleno mediada por Bacillus atrophaeus CN4

Squamocin belongs to a group of compounds called annonaceous acetogenins. They are secondary products of Annonaceae metabolism and can be isolated from Annona cherimolia seeds. This paper deals with the stimulation of biofilm formation of Bacillus atrophaeus CN4 by employing low squamocin concentrations to increase naphthalene degradation. Bacillus atrophaeus CN4, isolated from contaminated soil, has the ability to degrade naphthalene as the only source of carbon and energy. In the absence of additional carbon sources, the strain removed 69% of the initial concentration of naphthalene (approx. 0.2 mmol/l) in the first 12 h of incubation. The addition of squamocin in LB medium stimulated Bacillus atrophaeus CN4 biofilm formation and enhanced naphthalene removal. Squamocin (2.5 pg/ml) does not affect planktonic growth and therefore, the observed increases are solely due to the stimulation of biofilm formation.

Squamocin pertenece a un grupo de compuestos llamados acetogeninas annonáceas (ACG). Las ACG son productos secundarios del metabolismo de plantas de la familia Annonaceae y se pueden aislar a partir de semillas de Annona cherimola. Este artículo trata de la estimulación de la formación de biofilm de Bacillus atrophaeus CN4 mediante el empleo de bajas concentraciones de squamocin para optimizar la degradación de naftaleno. B. atrophaeus CN4, aislado de suelo contaminado, tiene la capacidad de emplear naftaleno como única fuente de carbono y energía. En ausencia de fuentes de carbono adicionales, la cepa degradó el 69% de la concentración inicial de naftaleno (aprox. 0,2 mmol/l) en las primeras 12h de incubación. La adición de squamocin en medio LB estimula la formación de biofilm y la remoción naftaleno de B. atrophaeus CN4. Squamocin (2,5 µg/ml) no afecta al crecimiento planctónico y, por lo tanto, los incrementos observados se deben únicamente a la estimulación de la formación de biofilm.

Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas

ABSTRACT The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94 ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R2 = 1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site.

Medium optimization for palmarumycin C13 production in liquid culture of endophytic fungus Berkleasmium sp. Dzf12 using response surface methodology

Background: Berkleasmium sp. Dzf12, an endophytic fungus from Dioscorea zingiberensis, was a high producer of palmarumycin C13 with various bioactivities. In the present study, the experimental designs based on statistics were employed to evaluate and optimize the medium for palmarumycin C13 production in mycelia liquid culture of Berkleasmium sp. Dzf12. Results: Among various carbon and nitrogen sources, glucose, peptone and yeast extract were found to be the most favourable for palmarumycin C13 production based on the one-factor-at-a-time experiments. After Plackett-Burman test on the medium, glucose, peptone and yeast extract were further verified to be the most significant factors to stimulate palmarumycin C13 accumulation. These three factors (i.e., glucose, peptone and yeast extract) were then optimized through the experiments of central composite design (CCD) and analysis of response surface methodology (RSM). The optimized medium compositions for palmarumycin C13 production were determined as 42.5 g/l of glucose, 6.5 g/l of peptone, 11.0 g/l of yeast extract, 1.0 g/l of KH2PO4, 0.5 g/l of MgSO4 x 7H2O, 0.05 g/l of FeSO4 x 7H2O, and pH 6.5. Under the optimal culture conditions, the maximum palmarumycin C13 yield of Berkleasmium sp. Dzf12 was increased to 318.63 mg/l, which was about 2.5-fold in comparison with that (130.44 mg/l) in the basal medium. Conclusions: The results indicate that the optimum production of palmarumycin C13 in Berkleasmium sp. Dzf12 liquid culture can be achieved by addition of glucose, peptone and yeast extract with their appropriate concentrations in the modified Sabouraud medium.

Interactions of carbohydrates and proteins by fluorophore-assisted carbohydrate electrophoresis.

A sensitive,specific, and rapid method for the detection of carbohydrate-protein interactions is demonstrated by fluorophore-assisted carbohydrate electrophoresis (FACE). The procedure is simple and the cost is low. The advantage of this method is that carbohydrate-protein interactions can be easily displayed by FACE, and the carbohydrates do not need to be purified.

Hydrolysis of organophosphorus compounds by an esterase isozyme from insecticide resistant pest Helicoverpa armigera.

Esterase activity of resistant and susceptible H. armigera were compared in gels with different substrate such as naphthyl acetate, naphthyl phosphate, paraoxon and monocrotophos. Whole body extract of resistant H. armigera hydrolyzed paraoxon, monocrotophos and naphthyl phosphate in gels. Resistant H. armigera showed high esterase, phosphatase and paraoxon hydrolase activity compared to susceptible ones.

Degradation of naphthalene by a Pseudomonas strain NGK1.

A Pseudomonas strain NGK1 capable of degrading naphthalene as a sole carbon source was isolated from biological waste treatment effluent. After 48 hr of incubation in 0.1% naphthalene mineral salts medium, the bacterial culture showed irregular clumped cells and salicylic acid (68 micrograms per ml) in the medium (pH 3.8). The strain degraded naphthalene through salicylate and catechol as was evidenced by metabolite characterization, oxygen uptake and enzymatic studies.