Production of rhamnolipids in solid-state cultivation: Characterization,downstream processing and application in the cleaning of contaminated soils

Pseudomonas aeruginosa UFPEDA 614 produced a rhamnolipid biosurfactant when grown on sugarcane bagasse impregnated with a solution containing glycerol. Biosurfactant levels reached 40 g of rhamnolipid per kilogram of dry initial substrate after 12 days. On the basis of the volume of liquid used, the biosurfactant levels were similar to those obtained in submerged liquid culture of a medium identical to the impregnating solution. The properties of the biosurfactant were very similar to those obtained with rhamnolipids produced in submerged culture, with a critical micelle concentration of 46.8 mg/L and an emulsification index at 24 h of over 90% against gasoline. The surface properties were maintained after autoclaving of the fermented solids, meaning that it is possible to minimize safety risks by killing the producing organism with a heat treatment of the solids prior to product extraction. The biosurfactant was used in the washing of soils contaminated with gasoline. An aqueous biosurfactant solution was 3.2-fold more efficient than water in leaching organic material from the soil, demonstrating the viability of application of rhamnolipids in the bioremediation of soils contaminated with gasoline.     

Intraspecific trait variability and genetic diversity in the adaptive strategies of serpentine and non-serpentine populations of Silene paradoxa L.

Plant and Soil - We investigated whether individuals of Silene paradoxa L., grown in serpentine and non-serpentine soils, displayed variation in functional traits and adaptive strategies...     

Structures of HCMV Trimer reveal the basis for receptor recognition and cell entry

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Luteolin, a bioactive flavone compound extracted from Cichorium endivia L. subsp. divaricatum alleviates the harmful effect of salinity on maize

The flavone luteolin was extracted, isolated and purified from leaves of Cichorium endivia L. subsp. divaricatum and identified based on ¹H and ¹³C NMR spectral analyses. Luteolin (0.0015?%) was applied to two cultivars of maize (Giza 2 and single cross 10) grains, germinated in the absence and presence of NaCl, in order to assess the bioactivity of luteolin and its role in alleviating the harmful effect of salt stress on maize. The results showed that luteolin enhanced germination and seedling growth of both maize cultivars in normal conditions. Furthermore, luteolin successfully alleviated the harmful effect of salinity on germination and seedling growth of maize. The potential role of luteolin was performed mainly by stimulating ??-amylase activity leading to enhancing starch mobilization and increasing the accumulation of soluble sugars, and partially by enhancing the antioxidative defense. As future prospective, a great number of phenolic compounds need to be screened in order to make use of them in improving agriculture under stressful conditions.     

Typing of Genetic Markers Involved in Stress Response by Fluorescent cDNA-Amplified Fragment Length Polymorphism Technique

Identification of genetic markers involved in stress response to physical factors or chemical substances in organisms is a challenging task. Typing of upregulated gene expression due to selective antibacterial pressure is a promising approach in the search of molecular mechanisms responsible for development of resistance. cDNA-Fluorescent Amplified Fragment Length Polymorphism (cDNA-FAFLP) strategy was developed and applied in the search of antimycotic drug resistance marker(s) in medically important fungi as an alternative method to microarray analysis. We compared differential gene expression of two sensitive Candida albicans reference strains (ATCC 10231 and ATCC 60133) and two of their paired resistant to fluconazole and itraconazole mutants. Resistant mutants Candida albicans FLC-R, resistant to fluconazole (MIC > 128 μg/ml) and Candida albicans ICZ-R, resistant to itraconazole (MIC > 4 μg/ml) were obtained in subcultures with gradual increase of the antifungal in the culture medium. cDNA-AFLP profile in both itraconazole resistant mutants showed specific spectrophotometric peaks with 5–6-fold RNA overexpression product of 500 bp length compared to the sensitive strains. Fluconazole mutants do not reveal RNA level changes under tested by us typing conditions. These results indicate that the cDNA-FAFLP strategy is a relatively rapid, simple, and reliable method for simultaneous typing of both constitutive and induced differences in expression of host genes providing insight into the biological processes involved in response to drugs in bacteria and fungi. Moreover, this methodology could be tested for typing of the genome response of any organism to physical or chemical stress factors.     

Untangling spider silk evolution with spidroin terminal domains

Background  

Spidroins are a unique family of large, structural proteins that make up the bulk of spider silk fibers. Due to the highly variable nature of their repetitive sequences, spidroin evolutionary relationships have principally been determined from their non-repetitive carboxy (C)-terminal domains, though they offer limited character data. The few known spidroin amino (N)-terminal domains have been difficult to obtain, but potentially contain critical phylogenetic information for reconstructing the diversification of spider silks. Here we used silk gland expression data (ESTs) from highly divergent species to evaluate the functional significance and phylogenetic utility of spidroin N-terminal domains.     

Analysis of alpha-fetoprotein heterogeneity by an improved crossed immunoaffinoelectrophoretic technique

The crossed immunoaffinoelectrophoretic procedure described here for the analysis of alpha-fetoprotein heterogeneity includes three major modifications of a procedure previously used by others: impregnation of the second dimension gel with methylated sugar derivatives; rigorous gel washing at 37 degrees C with the same derivatives; and an immunostaining technique. These simple changes have resulted in clear, sharp electrophoretic patterns at levels of total alpha-fetoprotein as low as 50 ng/ml, a sensitivity not previously approached with the method. Individual peaks representing as little as 7.5 ng/ml can be identified.