Decolorization of synthetic dyes by basidiomycetes isolated from woods of the Atlantic Forest (PE), Brazil

In this study, the biodegradability of synthetic dyes used in the textile industry by Basidiomycetes collected in woods of the Atlantic Forest of Pernambuco, Brazil, was evaluated. Among the fungi, the following species were identified: Caripia montagnei, Datronia caperata, Earliella scabrosa, Fomitopsis feei, Ganoderma stiptatum, Hexagonia hydnoides, Pleurotus ostreatus, Pycnoporus sanguineus and Trametes membranacea. Mycelium discs (2 cm2) of each fungal isolate were transferred to 30 ml of King medium supplemented with 0.05% m/v of each of the following dyes: methyl orange, bromophenol blue (BB), methylene blue, Congo red, phenol red (PR) and methyl green (MG). All these species showed potential to decolorize the tested dyes, with decolorization efficiency varying from 7.26 to 99.2%. H. hydnoides and T. membrancea were the only species able to degrade all dyes. BB was effectively metabolized by P. sanguineus (97.4%), H. hydnoides (95.6%), E. scabrosa (96.6%) and T. membranacea (99.2%). E. scabrosa stood out among the isolates in dyes decolorization, allowing for efficiencies >90% for MG, PR, and BB.     

Effect of humic acids from Leonardite on the stability of soil aggregates and melon roots under greenhouse conditions

Leonardite is an oxidized form of lignite carbon, which is obtained from fossilized organic materials. Such materials are used for the extraction of humic acids (HA). The result of the addition of HA of organic origin on soil structure is known; however, the effects of adding HA of Leonardite on soil structure have been scarcely investigated. The objectives of this research were (1) to determine the influence of humic acids derived from Leonardite in increasing the aggregate stability of an Aridisol under greenhouse conditions, and (2) evaluate the morphology of the root xylem during the phenological development of melon plants (Cucumis melo L.). Three treatments of HA solution application to the soil were used: soil without solution application (HA0), and application of HA solution to the soil with pH 6 (HA6) or (HA7). Aggregate stability (As) and bulk density (Da) were evaluated as soil variables. Development and quantification of xylem area were studied on plants. There were significant differences in aggregate stability. Also, there was an increase in the root xylem area, and the best treatment was when AH7 solution was applied. Humic acids derived from Leonardite increased the stability of soil aggregates when plants grew under greenhouse conditions, and fostered the development of xylem conduits during the fruiting stage.     

Variables that Affect Immobilization of Mucor Miehei Lipase on Nylon Membrane

Nylon membrane was used to immobilize Mucor miehei lipase. Variables that affect this immobilization procedure were studied by experimental design. A 2³ full factorial design was employed for this purpose. The protein retention and hydrolytic activity of the immobilized lipase were used as response variables. The rapid loss of enzyme activity was the main problem during repetitive use. Two strategies were used to improve the low operational stability: nylon treated with HCl and nylon coated with polyvinyl alcohol (PVA). Lipase-nylon-PVA was the best enzyme derivative, allowing performance of five consecutive assays, with a retained activity of 0.5 U mg of protein⁻¹ g of support⁻¹.     

Respiratory stimulus in Rhizobium sp. by legume lectins

High molecular weight lectins (> 100 kDa) from seeds of the legumes Canavalia brasiliensis (CnBr), Cratylia floribunda (CFL), Phaseolus vulgaris (PHA) and Vatairea macrocarpa (VML), temporarily stimulate the respiration of Rhizobium tropici-CIAT899 and R. etli-CFN42. These stimulants were significant (P < 0.05) in bacterial suspensions (> 2.85 mg dry biomass ml^–1), having at least 6200 molecules of lectins per bacteria. The VML (20 g ml^–1), induced specific O₂ demand of 2.3–2.5 M O₂ min^–1 mg dry biomass^–1, in CFN42 and CIAT899, respectively. However, CnBr, CFL and PHA induced smaller demands of O₂ (5×), in both strains. The order of affinities of the lectins was approximately VML > PHA > CFL > CnBr, with regard to respiratory stimuli in CIAT899 strain. The co-administration of 10 g VML ml^–1 and 9.8 M galactose, in CIAT899 suspensions, reduced the respiratory stimuli significantly in relation to the treatment with VML alone. These respiratory stimuli, induced by the lectins, increase the significance of the interaction lectin × Rhizobium in terms of bacterial physiology. Its understanding could be important in relation to bacterial symbiotic behaviour.     

Hon-yaku: a biology-driven Bayesian methodology for identifying translation initiation sites in prokaryotes

Background  

Computational prediction methods are currently used to identify genes in prokaryote genomes. However, identification of the correct translation initiation sites remains a difficult task. Accurate translation initiation sites (TISs) are important not only for the annotation of unknown proteins but also for the prediction of operons, promoters, and small non-coding RNA genes, as this typically makes use of the intergenic distance. A further problem is that most existing methods are optimized for Escherichia coli data sets; applying these methods to newly sequenced bacterial genomes may not result in an equivalent level of accuracy.     

Purification of a Penicillium citrinum lipase by chromatographic processes

A lipase from a wild strain of Penicillium citrinum was purified by ammonium sulphate precipitation, gel filtration chromatography on a Superose 6 column and hydrophobic interaction chromatography (HIC) on a Phenyl Superose column. The yield and purification factor were 15.2% and 379 fold, respectively. The gel filtration step was efficiently scaled-up in a Superose 6 preparative grade column and after this step, the lipase was recovered in the form of a high molecular weight aggregate. The partial disaggregation of the complex was achieved by HIC and elution with 1.0% (w/v) CHAPS. The lipase produced by Penicillium citrinum forms a dimmer of 63?000 Da, as determined by SDS-PAGE, and it accumulates in the fermentation broth as high molecular weight aggregates (>2?00?000 Da). The analysis of the dimmer showed two subunits with similar molecular weights (31?000–33?000 Da) and isoelectric points (4.8–5.0).     

Differentiated evolutionary pathways in Haemulidae (Perciformes): karyotype stasis versus morphological differentiation

Extensive phenotypic diversity (size, colors and shapes) among species of Haemulidae is practically dissociated from the conservative cytogenetic pattern observed in this family. Detailed analyses indicate that karyotypic stasis is maintained even under the scrutiny of different chromosome investigation methods. Chromosomal banding patterns (endophenotype) of five Atlantic species are presented here: Conodon nobilis, Pomadasys corvinaeformis, Haemulon aurolineatum, H. plumierii and H. steindachneri, obtained by incorporating the base analog 5-BrdU, C-banding and staining with base-specific fluorochromes. Despite a few chromosomal specificities, relative karyotypic conservation was confirmed, corroborating earlier studies on this family. On the other hand, phenotypic patterns (exophenotype), identified by geometric morphometrics contrast visibly with the chromosomal conservation of this group. As such, the evolutionary rates of chromosomes and body morphology demonstrate clear asynchrony. Possible causes of karyotypic stasis in Haemulidae are discussed as well as the sharing of this condition with other Perciformes.