Scaffold- and serum-free hypertrophic cartilage tissue engineering as an alternative approach for bone repair.

Human adipose stem/stromal cell (ASC) spheroids were used as a serum-free in vitro model to recapitulate the molecular events and extracellular matrix organization that orchestrate a hypertrophic cartilage phenotype. Induced-ASC spheroids (ø = 450 µm) showed high cell viability throughout the period of culture. The expression of collagen type X alpha 1 chain (COLXA1) and matrix metallopeptidase 13 (MMP-13) was upregulated at week 2 in induced-ASC spheroids compared with week 5 (P < .001) evaluated by quantitative real-time PCR. In accordance, secreted levels of IL-6 (P < .0001), IL-8 (P < .0001), IL-10 (P < .0001), bFGF (P < .001), VEGF (P < .0001), and RANTES (P < .0001) were the highest at week 2. Strong in situ staining for collagen type X and low staining for TSP-1 was associated with the increase of hypertrophic genes expression at week 2 in induced-ASC spheroids. Collagen type I, osteocalcin, biglycan, and tenascin C were detected at week 5 by in situ staining, in accordance with the highest expression of alkaline phosphatase (ALPL) gene and the presence of calcium deposits as evaluated by Alizarin Red O staining. Induced-ASC spheroids showed a higher force required to compression at week 2 (P < .0001). The human ASC spheroids under serum-free inducer medium and normoxic culture conditions were induced to a hypertrophic cartilage phenotype, opening a new perspective to recapitulate endochondral ossification in vivo.

Initial biochemical and functional characterization of a 5'-nucleotidase from Xylella fastidiosa related to the human cytosolic 5'-nucleotidase I.

The 5'-nucleotidases constitute a ubiquitous family of enzymes that catalyze either the hydrolysis or the transfer of esterified phosphate at the 5' position of nucleoside monophosphates. These enzymes are responsible for the regulation of nucleotide and nucleoside levels in the cell and can interfere with the phosphorylation-dependent activation of nucleoside analogs used in therapies targeting solid tumors and viral infections. In the present study, we report the initial biochemical and functional characterization of a 5'-nucleotidase from Xylella fastidiosa that is related to the human cytosolic 5'-nucleotidase I. X. fastidiosa is a plant pathogenic bacterium that is responsible for numerous economically important crop diseases. Biochemical assays confirmed the phosphatase activity of the recombinant purified enzyme and revealed metal ion dependence for full enzyme activity. In addition, we investigated the involvement of Xf5'-Nt in the formation of X. fastidiosa biofilms, which are structures that occlude the xylem vessels of susceptible plants and are strictly associated with bacterial pathogenesis. Using polyclonal antibodies against Xf5'-Nt, we observed an overexpression of Xf5'-Nt during the initial phases of X. fastidiosa biofilm formation that was not observed during X. fastidiosa planktonic growth. Our results demonstrate that the de/phosphorylation network catalyzed by 5'-nucleotidases may play an important role in bacterial biofilm formation, thereby contributing novel insights into bacterial nucleotide metabolism and pathogenicity.

Antimicrobial activity and phytochemical profile from the roots of Lippia alba (Mill.) N.E. Brown

Lippia alba (Mill.) N.E. Brown (Verbenaceae) is commonly used in the Brazilian folk medicine to the treatment of gastric illnesses, diarrhea, fever, asthma, and as a tranquilizer. This work evaluated the antimicrobial activity of ethyl acetate, methanol and aqueous extracts from the roots of the L. alba using plates-holes diffusion assay and the phytochemical profile. The results obtained showed that the ethyl acetate and methanol extracts presented antimicrobial activity against Staphylococcus aureus (ATCC 6538P), Staphylococcus aureus (ATCC 6538) and Klebsiella pneumonia (ATCC 10031). Terpenoids, phenylpropanoids and sugars were detected in the phytochemical analysis.

Lippia alba (Mill.) N.E. Brown (Verbenaceae) é geralmente usada na medicina popular brasileira para o tratamento de doenças gástricas, febre, asma e como tranqüilizante. Este trabalho avaliou a atividade antimicrobiana dos extratos acetato de etila, metanol e aquoso das raízes de L. alba usando métodos de difusão em poços e o perfil fitoquímico. Os resultados obtidos mostraram que os extratos acetato de etila e metanol apresentaram atividade antimicrobiana contra Staphylococcus aureus (ATCC 6538P), Staphylococcus aureus (ATCC 6538) e Klebsiella pneumonia (ATCC 10031). Terpenóides, fenilpropanóides e açúcares foram detectados na análise fitoquímica.