Enhancement of the Amazonian Açaí Waste Fibers through Variations of Alkali Pretreatment Parameters

The açaí fruit depulping produces large amounts of long lignocellulosic fiber bundles that are disposed in the environment. Chemical pretreatments may improve açaí fibers favoring their usage in advanced materials. This work aimed to define optimal alkali reaction parameters to improve the properties of açaí fibers. Two NaOH concentrations (5 % and 10 %) and two reaction temperatures (80 °C and 100 °C) were tested. The raw and treated fibers were analyzed by scanning electron microscopy, Fourier transformed infrared spectroscopy, X‐ray diffraction, and thermal analyses. All the alkali pretreatments separated fibers from the bundles, unblocked pit channels by removing silicon structures, exposed the inner lignin, partially removed non‐cellulosic compounds, and raised the cellulose crystalline index. The highest temperature and NaOH content resulted in better cleaning and isolation of the fibers, while milder conditions better preserved the cellulose crystalline structure and thermal stability.     

Effect of curcumin-nanoemulsion associated with photodynamic therapy in breast adenocarcinoma cell line

Curcumin, a natural compound has several antineoplastic activities and is a promising natural photosensitizer used in photodynamic therapy. However, its low solubility in physiological medium limit the clinical use of curcumin. This study aimed to analyze the action of curcumin-nanoemulsion, a new and well-designed Drug Delivery System (DDS+) molecule, used as a photosensitizing agent in photodynamic therapy in an in vitro breast cancer model, MCF-7 cells. The empty nanoemulsion fulfils all necessary requirements to be an excellent DDS. Furthermore, the use of curcumin-nanoemulsion in photodynamic therapy resulted in a high phototoxic effect after activation at 440?nm, decreasing to <10% viable tumor cells after two irradiations and increasing the reactive oxygen species (ROS) production. The use of curcumin-nanoemulsion associated with photodynamic therapy resulted in an increase in the levels of caspase 3/7 activity for the studied MCF-7 cell model, indicating that this therapy triggers a cascade of events that lead to cell death, such as cellular apoptosis. In conclusion, curcumin-nanoemulsion proved to be efficient as a photosensitizing agent, had phototoxic effects, significantly decreased the proliferation of MCF-7 cells and stimulating the ROS production in combination with photodynamic therapy, so, this formulation has a great potential for use in treatment of breast cancer.     

Epiphytic cyanobacterial strains in the roots of Salvinia auriculata and the effect of light and nutrients on the production of heterocyst,akinete and hormogonia

Aquatic Ecology - In epiphytic associations, cyanobacteria form the periphyton with phytoplanktonic algae and with aquatic macrophytes. In this study, we found homocytous and heterocytous...     

Double-antigen sandwich ELISA based on chimeric antigens for detection of antibodies to Trypanosoma cruzi in human sera

BackgroundEnzyme-linked immunosorbent assays (ELISA) are generally the chosen test for Chagas disease (CD) diagnosis; however, its performance depends on the antigen preparation adsorbed to the solid phase, which may lead to false-positive results and cross-reactions. The use of chimeric recombinant antigens can overcome this limitation. Four chimeric antigens from Trypanosoma cruzi (IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4) were developed and evaluated in phase I, II and III studies using indirect ELISA as diagnostic platform. However, peroxidase-labeled secondary anti-human IgG antibody, which is employed in indirect ELISAs, limits its use for the detection of species-specific and class-specific antibodies. To overcome this limitation, peroxidase-labeled antigens can be utilized, diagnosing both acute or chronic infection, in a species and immunoglobulin class-independent manner, through the use of a double-antigen sandwich ELISA (DAgS-ELISA). We aimed to evaluate and validate the diagnostic performance of the chimeric antigens IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4 in the DAgS-ELISA platform.Methodology/Principal findingsDAgS-ELISA was optimized by checkerboard titration. In phase I study, 207 positive and 205 negative samples were evaluated. Cross-reactivity to other infections was also assessed using 68 samples. The selected conditions for the tests utilized 25 ng of antigen per well and the conjugate diluted at 1:2,000 for all molecules. In the phase I study, the areas under the curve of IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4 were 98.7%, 99.5%, 98.6% and 98.8%, respectively. Among the positive samples, IBMP-8.1 antigen classified 53 (25.6%) as false negative, IBMP-8.2, 27 (13%), IBMP-8.3, 24 (11.6%) and IBMP-8.4, 43 (20.8%), giving sensitivities of 74.4%, 87%, 88.4% and 79.2%, respectively. The only antigen that did not reach 100% specificity was IBMP-8.3, with 96.6%. IBMP-8.3 was also the only molecule to show cross-reactivity with HTLV.Conclusions/SignificanceDAgS-ELISA is a promising tool for immunodiagnosis, and despite the high AUC values, the performance of this assay was different from the values obtained by our group when using these antigens in the indirect ELISA, for this reason, improvements are being considered to increase the sensitivity of the DAgS-ELISA.     

The diversity of globin-coupled sensors

The recently discovered globin-coupled sensors (GCSs) are heme-containing two-domain transducers distinct from the PAS domain superfamily. We have identified an additional 22 GCSs with varying multi-domain C-terminal transmitters through a search of the complete and incomplete microbial genome datasets. The GCS superfamily is composed of two major subfamilies: the aerotactic and gene regulators. We postulate the existence of protoglobin in Archaea as the predecessor to the chimeric GCS.     

Floral ontogeny of Lecointea, Zollernia, Exostyles, and Harleyodendron (Leguminosae: Papilionoideae: Swartzieae s.l)

Floral initiation and development were examined using scanning electron microscopy in Exostyles venusta, Harleyodendron unifoliolatum, Lecointea hatschbachii, and Zollernia ilicifolia. Common features include (1) unidirectional sepal initiation, (2) simultaneous petal initiation, (3) unidirectional initiation of each stamen whorl (except in the antesepalous whorl in Lecointea and Exostyles), (4) overlap in time of initiation of the two stamen whorls, and (5) initiation of the carpel concurrently with petals. Significant developmental features include (1) the first sepal median abaxial in all except Lecointea where it is non-median abaxial; (2) intraspecific variation in petal aestivation in Exostyles, Harleyodendron, and Lecointea; (3) initiation of antepetalous stamens before the antesepalous ones in Zollernia, Exostyles, and Lecointea; and (4) ovule initiation before the carpel margins are fused in Exostyles. The stamen sequence has not been found in any other legumes. The following late developmental events distinguish the four genera from each other: copious hairs hold the anthers together as a domelike structure at anthesis in Harleyodendron; zygomorphy in Zollernia results from differing petal reflexion; late hypanthium in Exostyles, Lecointea, and Holocalyx (no hypanthium in Harleyodendron or Zollernia); and reflexed sepal lobes in Exostyles, Harleyodendron, and Zollernia but not in Holocalyx and Lecointea. The genera studied here are ontogenetically more similar to taxa of Sophoreae than to other Swartzieae that have been investigated. None of the taxa studied here has a ring meristem, the structure that characterizes the remaining swartzioid taxa studied elsewhere.     

Affiliation in Four Echimyid Rodent Species based on Intrasexual Dyadic Encounters: Evolutionary Implications

In this work we explored the evolution of sociality in cursorial echimyids by comparing affiliation among three species of Trinomys and one species of Thrichomys. We captured specimens of Trinomys yonenagae, Trinomys albispinus minor, and Thrichomys apereoides in areas of the Brazilian semiarid Caatinga, and Trinomys iheringi denigratus in one area of Atlantic Forest. For each species, we recorded 12 intra‐sexual dyadic encounters in a neutral arena (six between males and six between females) in order to test the hypothesis that species and sex influence level of affiliation. This response variable was assessed based on an affiliation index, calculated as the proportion of the total number of affiliative behaviors to the total number of social behaviors exhibited by the dyad during each encounter. Hypothesis test was performed by means of a parametric two‐way anova . The test was able to detect significant differences only among species, not among sexes. Trinomys yonenagae was the most affiliative species, while T. apereoides and T. albispinus minor were the most agonistic ones. Trinomys iheringi denigratus showed an intermediate pattern. We suggest, based on out‐group comparison, that affiliation in Trinomys increased in the lineage containing T. iheringi denigratus and T. yonenagae and that higher affiliation in the last species can be adaptive to the life in the desert‐like habitat where it lives.     

Leishmania infantum: Lipophosphoglycan intraspecific variation and interaction with vertebrate and invertebrate hosts

Interspecies variations in lipophosphoglycan (LPG) have been the focus of intense study over the years due its role in specificity during sand fly-Leishmania interaction. This cell surface glycoconjugate is highly polymorphic among species with variations in sugars that branch off the conserved Gal(β1,4)Man(α1)-PO(4) backbone of repeat units. However, the degree of intraspecies polymorphism in LPG of Leishmania infantum (syn. Leishmania chagasi) is not known. In this study, intraspecific variation in the repeat units of LPG was evaluated in 16 strains of L. infantum from Brazil, France, Algeria and Tunisia. The structural polymorphism in the L. infantum LPG repeat units was relatively slight and consisted of three types: type I does not have side chains; type II has one β-glucose residue that branches off the disaccharide-phosphate repeat units and type III has up to three glucose residues (oligo-glucosylated). The significance of these modifications was investigated during in vivo interaction of L. infantum with Lutzomyia longipalpis, and in vitro interaction of the parasites and respective LPGs with murine macrophages. There were no consequential differences in the parasite densities in sand fly midguts infected with Leishmania strains exhibiting type I, II and III LPGs. However, higher nitric oxide production was observed in macrophages exposed to glucosylated type II LPG.