Lactose-crosslinked fish gelatin-based porous scaffolds embedded with tetrahydrocurcumin for cartilage regeneration

Tetrahydrocurcumin (THC) is one of the major colourless metabolites of curcumin and shows even greater pharmacological and physiological benefits. The aim of this work was the manufacturing of porous scaffolds as a carrier of THC under physiological conditions. Fish-derived gelatin scaffolds were prepared by freeze-drying by two solutions concentrations (2.5% and 4% w/v), cross-linked via addition of lactose and heat-treated at 105 °C. This cross-linking reaction resulted in more water resistant scaffolds with a water uptake capacity higher than 800%. Along with the cross-linking reaction, the gelatin concentration affected the scaffold morphology, as observed by scanning electron microscopy images, by obtaining a reduced porosity but larger pores sizes when the initial gelatin concentration was increased. These morphological changes led to a scaffold's strength enhancement from 0.92 ± 0.22 MPa to 2.04 ± 0.18 MPa when gelatin concentration was increased. THC release slowed down when gelatin concentration increased from 2.5 to 4% w/v, showing a controlled profile within 96 h. Preliminary in vitro test with chondrocytes on scaffolds with 4% w/v gelatin offered higher metabolic activities and cell survival up to 14 days of incubation. Finally the addition of THC did not influence significantly the cytocompatibility and potential antibacterial properties were demonstrated successfully against Staphylococcus aureus

Overcoming seed dormancy in visgueiro-of-the-igapó (Parkia discolor)

This study aimed to evaluate the effects of pregerminative mechanical scarification treatments, as well as heat pre-treatments on the germination of visgueiro-of-the-igapó (Parkia discolor Spruce ex Benth.) seeds. The first experiment, with a completely randomized design and four repetitions, evaluated these pre-treatments: control (without pre-treatment); clipping at the distal portion; clipping at the proximal portion (hilum); clipping at the proximal and distal portions; scraping at the distal portion; scraping at the proximal portion; scraping at the proximal and distal portions; perforation of the husk with a soldering-iron; and perforation by pyrography. In the second experiment, with a completely randomized design and factorial 2 (heat: dry and wet) x 4 (temperature: 40ºC, 50ºC, 60ºC and 70ºC) x 5 (period of conditioning: 6, 16, 24, 30 and 48 hours), with three repetitions. The clipping or scraping of the seeds in the proximal portion and proximal and distal portions allowed faster imbibition of the seeds (143-163% in three days and half), and consequently, better germination (98-100% in four days), germination speed rate (1,351-1,460) and average time of germination (3 days). The pre-treatment with heat (wet and dry), under different temperatures and different conditioning periods did not overcome the dormancy of P. discolor seeds.O presente trabalho teve como objetivo avaliar os efeitos da aplicação de tratamentos pré-germinativos de escarificação mecânica, bem como pré-tratamentos com calor, sobre a germinação de sementes de visgueiro-do-igapó (Parkia discolor Spruce ex Benth.). No primeiro experimento, sob delineamento inteiramente ao acaso, com quatro repetições, foram avaliados os pré-tratamentostestemunha (sem pré-tratamento); desponte no lado distal; desponte no lado proximal; desponte nos lados distal e proximal; lixamento no lado distal; lixamento no lado proximal; lixamento nos lados distal e proximal; perfuração do tegumento com ferro-de-solda; e perfuração com pirógrafo. No segundo experimento, foi adotado o delineamento inteiramente casualizado, em esquema fatorial 2 (calorseco e úmido) x 4 (temperatura40ºC, 50ºC, 60ºC e 70ºC) x 5 (período de condicionamento6, 16, 24, 30 e 48 horas), com três repetições. O desponte ou lixamento das sementes na porção proximal e porções proximal e distal possibilitaram uma embebição mais rápida (143-163%, aos três dias e meio) e, conseqüentemente, melhores resultados de germinação (98-100%, aos quatro dias), do índice de velocidade de germinação (1,351-1,460) e do tempo médio de germinação (3 dias). Os pré-tratamentos com calor (úmido e seco), sob diferentes temperaturas, e por vários períodos de condicionamento não superaram a dormência de sementes de P. discolor

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Molecular Differentiation Of Leishmania Protozoarium Using Cds Quantum Dots As Biolabels

In this work we applied core-shell CdS/Cd(OH)2 quantum dots (QDs) as fluorescent labels in the Leishmania amazonensis protozoarium. The nanocrystals (8-9 nm) are obtained via colloidal synthesis in aqueous medium, with final pH=7 using sodium polyphosphate as the stabilizing agent. The surface of the particles is passivated with a cadmium hydroxide shell and the particle surface is functionalized with glutaraldehyde. The functionalized and non-functionalized particles were conjugated to Leishmania organisms in the promastigote form. The marked live organisms were visualized using confocal microscopy. The systems exhibit a differentiation of the emission color for the functionalized and non-functionalized particles suggesting different chemical interactions with the promastigote moieties. Two photon emision spectra (λexc=795nm) were obtained for the promastigotes labeled with the functionalized QDs showing a significant spectral change compared to the original QDs suspension. These spectral changes are discussed in terms of the possible energy deactivation processes.6097Medinitz, I.L., Tetsuo Uyeda, H., Goldman, E.R., Mattoussi, H., Quantum dot bioconjugates for imaging, labeling and sensing (2005) Nature Materials, 4, pp. 435-446Chen, F., Gerion, D., Fluorescent CdSe/ZnS nanocrystal-peptide conjugates for long-term, nontoxic imaging and nuclear targeting in living cells (2004) Nano Letters, 4 (10), pp. 27-1832Alivisatos, A.P., Semiconductor clusters, nanocrystals, and quantum dots (1996) Science, 271, pp. 933-937Medintz, I.L., Konnert, J.H., Clapp, A.R., Stanish, I., Twigg, M.E., Mattoussi, H., A fluorescence resonance energy transfer-derived structure of a quantum dot-protein bioconjugate nanoassembly PNAS, 101 (26), pp. 9612-9617Mamedova, N.N., Kotov, N.A., Rogach, A.L., Studer, J., Albumin-CdTe nanoparticle bioconjugates: Preparation, structure, and interunit energy transfer with antenna effect (2001) Nano Lett., 1, pp. 281-286Farias, P.M.A., Santos, B.S., De Menezes, F.D., Ferreira, R.C., Barjas-Castro, M.L., Castro, V., Moura Lima, P.R., Cesar, C.L., Investigation of red blood cell antigens with highly fluorescent and stable semiconductor quantum dots (2005) Journal of Biomedical Optics, 10 (4), pp. 440231-1044234Farias, P.M.A., Santos, B.S., De Menezes, F.D., Ferreira, R.C., Barjas-Castro, M.L., Castro, V., Moura Lima, P.R., Cesar, C.L., Core-shell CdS/Cd(OH)2 quantum dots: Synthesis and bioconjugation to target red cells antigens (2005) Journal of Microscopy, 219 (3), pp. 103-108Petrov, D.V., Santos, B.S., Pereira, G.A.L., Donegá, C.M., Size and band-gap dependences of the hiperpolarizability of CdxZnl-xS nanocrystals (2002) J. Phys. Chem. B, 106, pp. 5325-5334Santos, B.S., (2002) Obtenção de Nanopartículas de CdS em Sistemas Amorfos e a Investigação de suas Propriedades Ópticas Não-lineares em Meio Aquoso, , Doctoral Thesis, Recife, BrazilSolomons, G., Fhryle, C., (2004) Organic Chemistry, 7th Ed., , Wiley, New YorkGao, X.M., Rhodes, J., An essential role for constitutive Schiff base-forming ligands in antigen presentation to murine T cell clones (1990) The Journal of Immunology, 144 (8), pp. 2883-2890Silveira, T.G.V., Arraes, S.M.A.A., Bertolini, D.A., Teodora, U., Lonardoni, M.V.C., Roberto, A.C.B.S., Sobrinho, M.R., Shaw, J., Observações sobre o diagnóstico laboratorial e a epidemiologia da leishmaniose tegumentar no Estado do Paraná, sul do Brasil (1999) Revista da Sociedade Brasileira de Medicina Tropical, 32 (4), pp. 413-42