Genetic diversity of Histoplasma capsulatum strains in Brazil

This study establishes the genetic relatedness among Brazilian Histoplasma capsulatum samples obtained from different sources. A PCR-based random amplified polymorphic DNA (RAPD) assay was used to delineate polymorphisms among isolates in geographically diverse regions in Brazil. RAPD fingerprints revealed distinct DNA profiles and provided a high level of discrimination among H. capsulatum strains from different locations. Cluster I was composed of H. capsulatum isolates from the northeast region. The majority of strains from southeast and south were categorized as major cluster II. The strain 84564 from Rio de Janeiro State showed no genetic correlation to any of the isolates from the same state. The RAPD patterns of H. capsulatum isolates from Goias (Cluster III) were unrelated to DNA fingerprints observed among the other H. capsulatum strains (48% similarity). This study is the first report that stratifies the clusters of H. capsulatum strains from Brazil by molecular typing and associates them with the geographical origin.     

Synthesis of a novel superabsorbent hydrogel by copolymerization of acrylamide and cashew gum modified with glycidyl methacrylate

Novel superabsorbent hydrogels were manufactured using chemically modified cashew gum (CGMA) and acrylamide (AAm) as reactants. The route for the synthesis was feasible due to the incorporation of glycidyl methacrylate (GMA) into structure of cashew gum (CG) to form the cashew gum-methacrylated (CGMA), in an appropriate mixture water-DMSO, as solvent, and using TEMED as catalyst. Thereafter, the CGMA was copolymerized with AAm yielding (CGMA-co-AAm) hydrogels. The main characteristics of raw and the modified materials are reported in this paper. ¹³C NMR, ¹H NMR and FTIR spectroscopies confirmed the incorporation of vinyl groups, from GMA, into CG structure. By the spectrophotometry analyses, it was found that, ca. 82% of GMA was incorporated to the CG after 24 h of reaction. The cross-linking of CGMA or co-polymerization of CGMA with acrylamide leads to a hydrogel formation. Their gelation was characterized by FT-IR analysis. Alkaline hydrolysis at 40 °C for 3 and 4.5 h increased the water uptake (WU) capacity. Hydrolyzed CGMA-co-AAm hydrogels present higher values of WU (up to 1500) and may be classified as water superabsorbent material. Applications in agriculture, as soil conditioner, and in biomedical field, as biomaterial (scaffold) are being investigated.     

Effect of visible light on superoxide dismutase (SOD) activity in the red alga Gracilariopsis tenuifrons (Gracilariales, Rhodophyta)

Superoxide dismutase (SOD) was studied in the agarophyte Gracilariopsis tenuifrons. Similar SOD activity (130 ± 9U mg^-1) was observed in material from different regions of SouthAmerica, from different phases of the life cycle (gametophytes andtetrasporophytes), and from apical and basal sections of the thallus.In alga grown under a light-dark cycle, SOD activity in samples takenat different times exhibited a diurnal rhythm. The activity measured duringthe day phase was twice as much as during the night phase. This rhythm didnot persist under constant light, indicating light regulation of SOD activity.SOD activity was tested in algae submitted to different light intensities anddifferent wavelengths. It increased with the light intensity. The blue lightwavelength exerted a greater induction of SOD activity than other specificwavelengths.     

Polyelectrolyte complexes based on pectin-NH2 and chondroitin sulfate

This work reports on the formation and characterization of a polyelectrolyte complex based on pectin (PT), functionalized with primary amine groups (PT-NH₂), and chondroitin sulfate (CS). From the simple mixture of PT-NH₂ and CS, in acid conditions, it was formed a polyelectrolyte complex, labeled as PT-NH₂/CS complex, which was confirmed through FTIR spectroscopy. The electrostatic interactions among the protonated amine groups from PT-NH₂ and the sulfate groups from CS are responsible by complex formation. XRD patterns and thermal analysis showed that the complex formation disrupts some interactions present on the PT-NH₂ and CS, but on the other hand, others are created. SEM images showed that the PT-NH₂/CS complex presents a porous and rough morphology. PT-NH₂/CS complex is new material that maintains the properties of CS with synergic association of properties from both polymers, which could maximize its applicability as biomaterial, for example.